Does anyone out there know of any pubs in Sheffield where the following classic beers may be had:
Batemans Triple XB
Fullers London Pride
Wadsworth 6X

It's getting very difficult to find these anywhere outside of a bottle

You might want to try looking on the brewery web sites where they probably list stockists.

eg: Batemans (http://www.bateman.co.uk/our+beers/stockists/stockists+list)

Unfortunately, Sheffield isn't on this particular list.