the 2 isometry classes of irreducible [18,6,8]_2 codes are:

code no       1:
================
1 1 1 1 1 1 1 0 0 0 0 0 1 0 0 0 0 0
1 1 1 1 0 0 0 1 1 1 0 0 0 1 0 0 0 0
1 1 0 0 1 1 0 1 1 0 1 0 0 0 1 0 0 0
1 0 1 0 1 0 1 1 0 1 1 0 0 0 0 1 0 0
1 0 0 1 0 1 1 0 1 1 1 0 0 0 0 0 1 0
0 1 1 0 1 0 1 1 1 0 0 1 0 0 0 0 0 1
the automorphism group has order 23040
and is strongly generated by the following 9 elements:
(
1 0 0 0 0 0 0 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 0 0 1 0 0 0 0 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
0 0 0 0 0 0 0 0 1 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
0 0 0 0 0 0 0 0 0 0 1 0 
0 1 1 0 1 0 1 1 1 0 0 1 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 0 0 1 0 0 0 0 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 0 0 0 0 0 1 0 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
1 1 1 1 0 0 0 1 1 1 0 0 
1 1 0 0 1 1 0 1 1 0 1 0 
0 0 0 0 0 0 0 0 0 0 0 1 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
1 1 1 1 1 1 1 0 0 0 0 0 
0 0 0 0 1 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
0 0 0 0 0 0 0 0 1 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
1 0 1 0 1 0 1 1 0 1 1 0 
0 0 0 0 0 0 0 0 0 0 0 1 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 1 0 0 0 0 0 0 0 
1 1 1 1 1 1 1 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
1 1 1 1 0 0 0 1 1 1 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
1 0 0 1 0 1 1 0 1 1 1 0 
0 0 0 0 0 0 0 0 0 0 0 1 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
1 1 1 1 1 1 1 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
1 1 1 1 0 0 0 1 1 1 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
0 0 0 0 0 0 0 0 0 0 1 0 
0 0 0 0 0 0 0 0 1 0 0 0 
0 0 0 0 0 0 0 0 0 0 0 1 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
1 1 1 1 1 1 1 0 0 0 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
1 0 0 1 0 1 1 0 1 1 1 0 
1 0 1 0 1 0 1 1 0 1 1 0 
0 0 0 0 0 0 0 0 1 0 0 0 
0 0 0 0 0 0 0 0 0 0 1 0 
0 0 0 0 0 0 0 0 0 0 0 1 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
1 1 0 0 1 1 0 1 1 0 1 0 
0 0 0 1 0 0 0 0 0 0 0 0 
1 0 1 0 1 0 1 1 0 1 1 0 
0 0 0 0 1 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 1 0 0 0 
1 1 1 1 1 1 1 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 1 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 0 1 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
1 1 1 1 1 1 1 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
1 1 0 0 1 1 0 1 1 0 1 0 
1 1 1 1 0 0 0 1 1 1 0 0 
0 0 0 0 0 0 0 0 0 0 1 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
0 0 0 0 0 0 0 0 1 0 0 0 
0 0 0 0 0 0 0 0 0 0 0 1 
, 
1 1 1 1 0 0 0 1 1 1 0 0 
1 1 0 0 1 1 0 1 1 0 1 0 
0 0 0 0 1 0 0 0 0 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
1 0 1 0 1 0 1 1 0 1 1 0 
1 1 1 1 1 1 1 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 0 1 
)
acting on the columns of the generator matrix as follows (in order):
(12, 18), 
(8, 9)(10, 14)(11, 15)(16, 17), 
(5, 7)(6, 13)(11, 16)(15, 17), 
(5, 6)(7, 13)(8, 10)(9, 14)(11, 17)(15, 16), 
(3, 5, 13)(4, 6, 7)(8, 15, 14)(9, 11, 10), 
(3, 6, 7)(4, 5, 13)(8, 14, 17)(9, 10, 16), 
(2, 8, 15)(3, 10, 13, 7, 16, 4)(6, 11, 9)(14, 17), 
(2, 7, 13)(3, 8, 10)(4, 16, 15)(5, 17, 14)(6, 9, 11), 
(1, 15, 2, 14)(3, 4, 6, 5)(7, 11, 13, 10)(9, 16)
orbits: { 1, 14, 10, 9, 15, 8, 17, 2, 11, 3, 13, 16, 6, 5, 7, 4 }, { 12, 18 }

code no       2:
================
1 1 1 1 1 1 1 0 0 0 0 0 1 0 0 0 0 0
1 1 1 1 0 0 0 1 1 1 0 0 0 1 0 0 0 0
1 1 0 0 1 1 0 1 1 0 1 0 0 0 1 0 0 0
1 0 1 0 1 0 1 1 0 1 1 0 0 0 0 1 0 0
0 1 1 0 1 0 1 1 1 0 0 1 0 0 0 0 1 0
1 1 0 0 0 1 1 1 0 1 0 1 0 0 0 0 0 1
the automorphism group has order 2160
and is strongly generated by the following 8 elements:
(
1 0 0 0 0 0 0 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
0 0 0 0 0 0 0 0 1 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 0 1 0 0 0 0 0 0 0 
1 1 0 0 0 1 1 1 0 1 0 1 
1 1 0 0 1 1 0 1 1 0 1 0 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 1 1 0 1 0 1 1 1 0 0 1 
1 0 1 0 1 0 1 1 0 1 1 0 
0 0 0 0 1 0 0 0 0 0 0 0 
1 1 0 0 0 1 1 1 0 1 0 1 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 0 1 
0 0 0 0 0 0 0 0 1 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
1 1 1 1 0 0 0 1 1 1 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
1 1 1 1 0 0 0 1 1 1 0 0 
1 0 1 0 1 0 1 1 0 1 1 0 
0 0 0 0 0 1 0 0 0 0 0 0 
1 1 1 1 1 1 1 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 1 0 
0 0 0 0 0 0 0 0 1 0 0 0 
1 1 0 0 1 1 0 1 1 0 1 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
0 1 1 0 1 0 1 1 1 0 0 1 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
0 0 0 0 1 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 1 0 
0 1 0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 1 0 0 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 1 1 0 1 0 1 1 1 0 0 1 
, 
1 0 0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 0 1 
0 0 1 0 0 0 0 0 0 0 0 0 
1 1 0 0 1 1 0 1 1 0 1 0 
0 1 1 0 1 0 1 1 1 0 0 1 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
0 0 0 0 0 0 0 0 1 0 0 0 
1 1 0 0 0 1 1 1 0 1 0 1 
1 1 1 1 1 1 1 0 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
, 
0 0 0 0 0 0 0 0 0 0 1 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
0 0 0 1 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 1 0 0 0 0 
0 1 0 0 0 0 0 0 0 0 0 0 
1 0 1 0 1 0 1 1 0 1 1 0 
0 0 0 0 1 0 0 0 0 0 0 0 
1 1 0 0 1 1 0 1 1 0 1 0 
0 0 1 0 0 0 0 0 0 0 0 0 
1 0 0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 0 1 
, 
1 0 1 0 1 0 1 1 0 1 1 0 
0 0 1 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 1 0 0 0 
1 1 0 0 1 1 0 1 1 0 1 0 
1 0 0 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 0 1 0 
0 0 0 0 0 0 0 1 0 0 0 0 
1 1 1 1 0 0 0 1 1 1 0 0 
0 0 0 0 0 0 0 0 0 0 0 1 
, 
1 1 0 0 0 1 1 1 0 1 0 1 
0 0 0 0 1 0 0 0 0 0 0 0 
1 1 0 0 1 1 0 1 1 0 1 0 
0 0 0 0 0 0 1 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 1 0 0 
0 0 0 0 0 0 0 0 0 0 1 0 
0 0 0 0 0 0 0 0 0 0 0 1 
1 0 1 0 1 0 1 1 0 1 1 0 
0 1 1 0 1 0 1 1 1 0 0 1 
0 1 0 0 0 0 0 0 0 0 0 0 
1 1 1 1 0 0 0 1 1 1 0 0 
0 0 0 0 0 1 0 0 0 0 0 0 
)
acting on the columns of the generator matrix as follows (in order):
(5, 10)(6, 8)(7, 9)(11, 18)(12, 15)(13, 14)(16, 17), 
(3, 17)(4, 16)(6, 18)(8, 12)(11, 14)(13, 15), 
(2, 15, 8, 14)(3, 13, 5, 16)(4, 10, 11, 6)(7, 9)(12, 17), 
(2, 5)(3, 8)(4, 11)(7, 9)(12, 17)(13, 15)(14, 16), 
(2, 12)(4, 15)(5, 17)(10, 18)(11, 13)(14, 16), 
(1, 11)(2, 6)(3, 10)(5, 8)(7, 16)(9, 15), 
(1, 8, 10, 4, 16)(2, 13, 15, 7, 3)(5, 14, 11, 9, 6), 
(1, 14, 11, 6, 12, 7, 4, 16, 8, 17, 9, 13, 15, 3, 18)(2, 10, 5)
orbits: { 1, 11, 16, 18, 14, 10, 4, 13, 17, 5, 7, 6, 3, 8, 2, 15, 9, 12 }