Furry-ferrets sent me an email with further help on the Monks Cave cache and also the Thorpe Wood Nature Reserve cache which I've tried a few times.
So this lunchtime TT925, McDan1 and I went out to try these again. We started with Monks Cave and found it instantly, now that it had been replaced. Unfortuntely a couple of fisher muggles turned up abnd started fishing practically in GZ so I could not replace. (We had to take it with us and I replaced it on my way home from work.)
Then we went down to the nature reserve and parked up over the road and MacDan found the cache before I'd even got the GPS up on the phone!
Following out success here we popped along to have a look at longthorpe ecole primaire and had an easy find here too.