car disc lock

[cred]

hi guys,
wondered if anyone can help?
got a job this morning from a guy who has a steering wheel disc lock on his car (thatcham approved), and when you turn the key to unlock it, the lock is supposed to pop open but this is just poping a tiny bit,not fully.
so i tryed prising it ect but no joy,anybody had this problem before?,the guy dose no mind if it has to be damaged ,just wants it off (5 year guarentee).
any ideas guys please pm me
cheers
ray

[AUTOLOX]

This may be a bit late but here goes
I do not know if this was the same make, but I had the same problem. I thought it was going to be hard work as it had a revolving hard plate to prevent direct drilling, so i drilled the cover (which has no protection ) in four places, bent cover out of the way and pulled the whole lock out. Turns out there is a plastic spacer which just fell apart, which meant the lock was being pushed too far up by the spring so I would try pushing down hard on the lock while turning the key.

Oh by the way, the customer had three other locksmiths out whose advice ranged from grinding to crowbar to removing steering column. customer was so happy I got £20 tip