To try & pinpoint the cause of a condensation problem I'm looking for
a combined thermometer and humidistat / hygrometer (AFAIK the same
thing) to record and store measurements at intervals, eg once every 15
minutes over, say, a 24 hour period. It would be good if it could
download to a PC, but not essential.

I've had a good hunt around the web & while I can find loads that will
store a max & min at around £20, I can't find anything that will just
store readings at set intervals, which costs less than several hundred
quid.

Any suggestions?

Michael