Just an update on proceedings: I have played TF2 for about 8 hours since the Engy update and haven't yet had a crash again. Whether it is just being temperamental or this has fixed it remains to be seen. This is still the only game that has been crashing for me over the weeks, so it does seem to be just TF2 related, rather than the 'other' things that are also wrong with my computer.

I shall keep you posted.

Well, havent got any map change related crashes recently but some ingame and one in particular: Sometimes when I try to play demoman and I join a server and then fire the game instantly goes down :/ but it repeats itself everytime i try.

An update for Team Fortress 2 is now available. Here are the specific changes:

Server Browser:
- Fixed the server browser not saving filter settings properly.

Team Fortress 2:
- Fixed a speed exploit related to benchmarks.
- Fixed Parasite hat not being posed correctly on class loadout panels.
- Fixed a level change crash.

Good news if that is the particular crash. Although the game still hasn't crashed for me since the Engy update anyhow, so that may have already fixed it.

However, fingers are as ever crossed...