The pin is fully floating on the vauxhall in both the piston and the rod.

All the info you could ever want about LET pistons is here mate:
http://www.vauxhall-sport-forum.com/...let-t3546.html


Including:

Gudgeon pin diameter.............21mm
Gudgeon pin fit in piston........Clearance 0,004/0,010mm
Gudgeon pin fit in con rod.......Clearance 0,015/0,030mm


And:

Piston Clearance in bore.........0,05/0,07mm

If you are likely to be working it quite hard, be at the top end of that piston to bore clearance range, it still wont slap.