Evil Twin now have a TF2 server that we're free to use: 184.108.40.206:27022. Thanks to Simon (aka ExtremeOne) at ET for the info, and for allowing us to use their servers in general - much appreciated by all at DFC.
Talking of TF2, I spotted in the release notes for yesterday's TF2 update:
Added the ability for servers to have map-specific .cfg files in the cfg folder
If this is engineered into CS:Source, it means we could set map-specific gravity, weapon restrictions etc without mincing around after map-load.