Dear GAP forum, dear Primoz,
it is possible to determine a pc presentation for B(2,6) using Alice
Niemeyer's soluble quotient algorithm. This algorithm is available
in GAP 3 and it will produce a GAP 3 readable pc presentation of B(2,6).
Further, I have a GAP 4 readable pc presentation of B(2,6). This is
probably more useful, since GAP 4 is the current version of GAP. Since
the presentation is fairly long, I will send it to you in a separate
e-mail.
Best wishes, Bettina