Yay, I have a frog!

I'm probably about half a mile from the nearest body of water that I know of, but yesterday I found a really quite enormous frog on my allotment, living quite happily under the courgettes.  I always make a point of leaving a couple of large, flat containers of water on my plot for wildlife but I'm a bit worried about how this guy is going to survive the winter.  I guess there must be a stream or something nearby where he can hibernate.  Can I build him some sort of frog shelter?

Also, has anyone else found any unexpected wildlife on their plot?

Is the frog enormous or just big ? If its really big its probably an exotic pet that has been turned loose , when fishing i`ve seen a few whoppers (not anglers tall tales) bullfrogs and strange toads that are 4 or 5 times the size of our native frogs.

I only just finished making a large new shade flower garden and as I watered today I found a young toad hopping under the hosta leaves. Nothing at all could live there before, it was so dry and hard.