[quote=echinosum;933425]Helps to know where in the world you are, so that lemurs can also be ruled out, etc.

You're quite right! I didn't realise that this forum had an international readership. I should have mentioned my location.

I'm in the North East of England where, fortunately, we don't see many bunyips! You may be right about it being a badger. Other suggestions have included some creature with a wooden leg or a pogo stick which might account for the holes. Either way, we blocked up the gaps under the fence and there's no sign of its having returned last night.

Thanks to everyone for the replies so far. Other ideas are always welcome.

GDMc