the 3 isometry classes of irreducible [8,3,4]_2 codes are:

code no       1:
================
1 1 1 1 1 1 0 0
1 1 1 0 0 0 1 0
1 1 0 1 0 0 0 1
the automorphism group has order 32
and is strongly generated by the following 4 elements:
(
1 0 0 0 0 
0 1 0 0 0 
0 0 1 0 0 
0 0 0 1 0 
1 1 1 1 1 
, 
1 0 0 0 0 
0 1 0 0 0 
1 1 0 1 0 
1 1 1 0 0 
1 1 1 1 1 
, 
1 0 0 0 0 
0 1 0 0 0 
0 0 0 1 0 
0 0 1 0 0 
0 0 0 0 1 
, 
0 0 0 0 1 
1 1 1 1 1 
0 0 0 1 0 
0 0 1 0 0 
0 1 0 0 0 
)
acting on the columns of the generator matrix as follows (in order):
(5, 6), 
(3, 8)(4, 7)(5, 6), 
(3, 4)(7, 8), 
(1, 6, 2, 5)(3, 4)
orbits: { 1, 5, 6, 2 }, { 3, 8, 4, 7 }

code no       2:
================
1 1 1 0 0 1 0 0
1 1 0 1 0 0 1 0
1 1 0 0 1 0 0 1
the automorphism group has order 384
and is strongly generated by the following 8 elements:
(
1 0 0 0 0 
0 1 0 0 0 
0 0 1 0 0 
0 0 0 1 0 
1 1 0 0 1 
, 
1 0 0 0 0 
0 1 0 0 0 
0 0 1 0 0 
1 1 0 1 0 
0 0 0 0 1 
, 
1 0 0 0 0 
0 1 0 0 0 
0 0 1 0 0 
1 1 0 0 1 
0 0 0 1 0 
, 
1 0 0 0 0 
0 1 0 0 0 
0 0 0 1 0 
1 1 1 0 0 
0 0 0 0 1 
, 
1 0 0 0 0 
0 1 0 0 0 
1 1 0 0 1 
1 1 1 0 0 
0 0 0 1 0 
, 
0 1 0 0 0 
1 0 0 0 0 
0 0 1 0 0 
0 0 0 1 0 
0 0 0 0 1 
, 
1 1 1 0 0 
0 0 1 0 0 
1 0 0 0 0 
0 0 0 1 0 
0 0 0 0 1 
, 
0 0 0 0 1 
1 1 0 0 1 
0 1 0 0 0 
1 1 0 1 0 
1 1 1 0 0 
)
acting on the columns of the generator matrix as follows (in order):
(5, 8), 
(4, 7), 
(4, 5, 7, 8), 
(3, 7, 6, 4), 
(3, 7, 8)(4, 5, 6), 
(1, 2), 
(1, 3, 2, 6), 
(1, 6, 5)(2, 3, 8)(4, 7)
orbits: { 1, 2, 6, 5, 3, 8, 7, 4 }

code no       3:
================
1 1 1 0 0 1 0 0
1 1 0 1 0 0 1 0
1 0 1 1 1 0 0 1
the automorphism group has order 48
and is strongly generated by the following 4 elements:
(
1 0 0 0 0 
0 1 0 0 0 
0 0 1 0 0 
0 0 0 1 0 
1 0 1 1 1 
, 
1 0 0 0 0 
0 1 0 0 0 
1 1 1 0 0 
1 1 0 1 0 
0 0 0 0 1 
, 
1 0 0 0 0 
0 1 0 0 0 
0 0 0 1 0 
0 0 1 0 0 
0 0 0 0 1 
, 
1 1 0 1 0 
0 0 0 1 0 
1 1 1 0 0 
1 0 0 0 0 
0 0 0 0 1 
)
acting on the columns of the generator matrix as follows (in order):
(5, 8), 
(3, 6)(4, 7), 
(3, 4)(6, 7), 
(1, 4, 2, 7)(3, 6)
orbits: { 1, 7, 4, 6, 2, 3 }, { 5, 8 }