I posted too soon back in December. Since then, we've been plagued with error messages for no obvious reasons. Sometimes it worked, sometimes not.
After 6 months of problems, I
think I've now fixed it

.
Well actually, I managed to completely replace it without erasing the original database of postings - more a matter of courage than skill.
Please visit it at
http://www.wvcc.org.uk/smf2/ (new address) http://www.wvcc.org.uk/smf/. If you get a flood of error messages as often happened previously, please let me know.
Incidentally, there's a forum software upgrade available but I'll wait a coupla weeks before doing that.
<amended address 2010-08-21>