Yes, its probably rats - Tree Rats (squirrels).
If it is ordinary rats then the council do two visits for £50.
If its squirrels you have to get wallet-raked by a private company. Two visits are just under £100 for poisoning or just over £100 for traps. You also need to get the entrance sealed otherwise it happens again. Traps are better, you don't want dead squirrels rotting away in some hidden corner.
You need to get it done soon as they love to chew through mains cables.
Edited by diggingdeeper (24th Oct 2016 12:23pm)
In a time of universal deceit - telling the truth is a revolutionary act. George Orwell
When the debate is lost, slander becomes the tool of the loser. Socrates