I think these are parrot waxcaps in various stages. Spotted among trees at the edge of pasture in east Sussex. #mastodonmushrooms
https://www.wildfooduk.com/mushroom-guide/parrot-waxcap/
Parrot Waxcap

A spectacular mushroom with varied colours, mainly between green, yellow and blue with a shiny, slimy cap and stem. As with most waxcaps this mushroom should be left alone to grow and be appreciated as it is not common and is rather inedible due to its sliminess.

Wild Food UK