Thanks to everybody who responded to my query about the squashes which were supposed to be butternuts, but clearly weren't. We're happy calling them the Buttercup/Kabocha type.
Anyway, we went down to the allotment today and brought them home with us. The plant was showing signs of a touch of frost,which was confirmed by the adjacent householders, although we've had no frost at home only 2 miles away. Also we're going to be a bit busy in the next few weeks, so home they came. There are a couple of pics of them here -
25 in the pics, plus about 5 or 6 small ones left on the plants just in case they do anything, and a couple given away already. 30+ from 2 plants, not bad, no?