Found one of these tonight under a plank of wood. It's a common grass snake. It was about a foot long, darker brown than this one. It was all curled up but hung around long enough for Lisa to tie the dog up and have a look. The yellow band around the neck was very striking.
Where we walk also plays host to the adder or viper. Black zig zags on the back. Best not to stand on one as their bite is poisonous and painful