I know that keeping a gunsafe in the loft seems a good idea from the security angle, but it's not. It all depends on access to your loft. Is there loft ladders in place or is it the step ladders ? The way the police see it, with rifles and shotguns, you are more liable not to put your guns away in safe after use straight away and to leave them out of harms way.
Have a rethink and look at other possible places. Try looking at disguising the safe using furniture but again access is a factor.
Also, please be mindful of telling where you keep your guns !