X300 with Intel 2100 mini PCI - connection problems

I'm having trouble with the Intel 2100 mini PCI card in my X300.

At work we use LEAP (so we can't use the Dell wireless cards...) with CISCO base stations and it works fine for a while but slows down eventually and frequently loses the connection.

I have a wide open network at home with a Belkin base station - again it works fine for a while, then loses the connection despite showing full coverage and even freezes up the x300.

I tried updating to the latest driver 1.2.3.10 with the effect that it seems to work fine at home but LEAP doesn't work at all so I can't use it at work.

Any suggestions? Any ideas for tests that I can run to figure out what the problem is?