As I asked for this, I'll explain myself...
Our plots are in North London, very near a major road, but despite this, rich in wildlife. We have all the usual - finches, thrushes, etc., but we also have Great Spotted & Green Woodpeckers, Kestrels and possibly Tawny Owls.
Several plots have ponds - we built our last year and have already spawned a good population of frogs.
We do have rats at the other side of the site - near a dairy and a building site, but the foxes catch them and the magpies bully the foxes out of their meal.
The plot next to us is abandoned and is home a to couple of foxes (Doug and Dinsdale) and at least one hedgehog (Norman). However, I have heard that this plot is about to be let and I'm worried that my little pals will be displaced.

At the far end of one our plots there is a 5 by 15 foot bank which I intend to turn over to wildlife and wildflowers. We have a large clump of Elder where I've already put one nesting box. How can I encourage the hedgehogs to stay?
And how high up would I have to put a Bat Box?