Yes, this is a type of Rove Beetle. It is an Ocypus olens. This beetle is usually 25-30mm long and is a very common European beetle. It is one of the larger British beetles and is also known as Devil's Coach-Horse Beetle.
I have never seen Ocypus olens with such a speckled complexion, which is why I thought the Ontholestes rove beetle was more likely. However, I'm sure we'll get some comment from the experts. If things run true to form, we could both be wrong!!
Yes now I've gone a name to search on I have to say this looks very much like it's a Ontholestes tesselatus! Thanks for the ID! Never seen one of these before so great to have a name for it.