Darn, should have checked the Forum! We went along late Sunday afternoon anyway to belatedly check out the park.
I googled for "Panshanger Park" beforehand for info (remembering the disussion on here about lack of signage) and got theFriends of Panshanger site
but there was no mention of a fun day on there that I could see.
Anyway as luck would have it we turned up at the Theives Lane car park about 4pm and there was a sign saying parking for the Fun Day on the way in. Once parked, there was a banner for the fun day and we found the notice board which had a poster advertising the fun day and listing all the fun activities but not further info about where it was. I know this topic has been done before but we couldn't find any further signs indicating where to go! I see from the link posted that there should have been signs to the parking area at Riverside Cottage but they eluded us.
We stuck to our original plans having looked at the map online and headed to the lake. We eventually did spot a load of cars in a field in the distance and met someone coming back who told us it was a long walk so probably not worth it (it was nearly over).
So yes, we shouldn't be spoonfed everything and use our initiative a bit but how do people find out about stuff like this? (we managed to get to the Malaysian festival the other weekend after someone posted it on here, thanks to whoever posted that) Thanks for codek2 for posting this but I'm definuitely with people who say the signs are somewhat lacking.