Doh, just seen this post!
Replied to the other one...
Okay, this looks to be £125-150. But you might find it'll take a while to find the right buyer - the re-issues have hurt the values of the maths set imparticular. But there are buyers still looking for GOOD vintage examples.
The stuff that fetches the really big money is are the items that did not make it to re-issue, like the pencil box and felt tips - and any display material is gold dust.