I've tried googling all sorts and now it's really bothering me. Lots of smart people here so I thought it worth a go...
Both plants grow in the same woods in Somerset where I walk the dog. The purple things are teeny and grow near a lake. The yellow ones (which look a bit like calla lilies to me) are mahoosive and grow in boggy areas all over the place. Both are flowering now.
Any ideas what they are?
edit: just found the purple ones are toothwort! Any help on the yellow ones would be great.