Those should be a type of amphibian salamander known as a newt. Lizards are reptiles, and I'm pretty sure those are amphibians. Do a quick search to see if any species of newts live in your area. I'm thinking those are some of them. There are 3 species of newts indigenous to the UK, with one of them being the Smooth Newt. Very cool creatures no matter what they are, and thanks for sharing the photos and story!