New Pond: advice and ideas welcome!

Back in 2005 when we moved into this place the garden flooded a few months after our arrival and half the garden was under water. Behind us was (and still is) a large expanse of unused, boggy grass between us and a housing estate. We asked the council and the housing association about getting it drained, but both denied ownership and the council's environmental health officer suggested we take over the land (which is un-claimed in the land registry) and drain it ourselves. It's taken us nearly 6 years but having had a temporary chain link fence, then more permanent concrete gravel board wall up, we've finally got round to doing something about the drainage (which has actually been much better anyway since the warehouse over the road had some trees removed and the sewer pipes were upgraded). What better way to improve drainage and create habitat than by making a pond??

As it was, flooded and used as a den/dumping ground for the local kids and fly-tippers:

A few weeks ago the whole area was very overgrown with 2 willows that had sprung up and very long grass. We've strimmed the grass, sadly evicting a couple of toads (who we've promised an awesome pond by way of compensation). It;s great to see we have some wildlife before we've even got any water!

And we've cleared out several tonne builder's bags worth of bricks, glass and plastic bottles, golf balls, most of a bedstead, PVC window frame, kitchen cupboard doors, one interior door, the rubber bit of a vibrator (yes, really!), socks, shoes... you name it!

There's a natural bower between the two willows that (if my dream comes true!) will get some decking / a pier looking over the pond:

Once the strimming and clearing was done, we hired a micro digger over the Royal Wedding weekend and got to work. After a LOT of hard work, we've been left with... a daunting and scarily large hole!

The photos don't really do it justice. It's about 10 x 7 x 0.3-0.5m depending on which bit you measure. There's a lot of conflicting advice on the net about depths of wildlife ponds, ranging from the 30cm mentioned in the eminently sensible link from the RSPB staff on another thread (http://www.pondconservation.org.uk/advice/makeapond/makeagardenpond) to ridiculous 1.5m suggestions! We need to do a lot of levelling and building of banks round our large hole to work out how deep the maximum and minimum are, but I would like to get the digger back and dig out the middle to a greater depth for extra safety in winter and to put some deeper plants like water lilies in. There's a slope at one end of the pond which will be a pebble shore for overflow, bird bathing etc. I'd like also to use some of the bricks we dug out to make some shelves for marginal plants too, and at the other end a shallow / bog section with a raised slate type fall down the middle.

Apart from actually doing some belated measurements, can anyone suggest anything we need to do / should do / would be nice to do?

Maisie