Majority view is that this is a Green Crab spider, Diaea dorsata, rather than a Lime Green Orb spider, Araneus cucurbitin.
Thanks to the following for their feedback via @wildlife_uk – http://www.wildlifesightings.co.uk/ @WayneVulcan1, @johnlamin1, @Beckbock and @1rosshirnie.
Picture taken December 2 by Andy after the spider dropped in on his survey sheet.
