How to make raised pond attractive to wildlife

I would like some advice on how to make a raised pond more wildlife
friendly.

First the pond: It is built using oak sleepers with a butyl liner
waiting to be fitted, and oak capping to hold the liner down. This
capping will over hang the inside edge by 2". The pond is 30" at the
deepest, with a 10" deep planting shelf running round 70% of the edge.
Built into a slope, one side is 24" above ground level with the other
only 12" above ground. Overall it has about 10.5 sq m surface area
(4.6 cu m volume) So far it has nothing in it, not even water!

It seems to me that the over hanging capping and the raised sides
present a barrier to wildlife, yet I hope it can be a home for frogs,
toads and newts etc. Not really wanting to keep fish (far too lazy a
gardener!), just make a wildlife haven with lots of water plants. I
hope that I can adapt this basic raised design to make this work.

My main idea is to construct a sloping flower bed or rockery on the
lowest sides (50%), so things can crawl up. But I still worry that
animals (invertebrates and otherwise) won't be able to get out of the
water because of the straight interior sides and over hanging capping.
I had thought about making a bog garden in one corner (inside the
liner), removing the capping at that point and have the rockery merge
into it, but I am not sure if this would cause either wicking or a bad
evaporation problem. Would the odd "ladder" of stones in a pile on
the planting shelf do the job?

Just how good is nature at over coming dumb man-made obstacles like
raised sides and over hangs?
Any suggestions welcome.

Dave