I'm just wondering if you could have a raised one with the soil you take out. I was thinking that when we did our last pond the shallow end was created by piling up the soil taken out from the shelf of the old pond and put straight up on the grass so that the depth in the old pond remained the same but the new longer shallows became shallow not by digging down but by piling up. (By - that was a long sentance
) Do you understand what I am trying to get at. I am just thinking that you could start your digging in the middle and pile all the way round. That way not having to dig out so much and having no problem getting rid of the soil.
Another thing I was going to ask was on the photo with the little bit of sun shining, is that the only time you get sun there or does it get a bit better as the day progresses. It looks like where it is now the sun will not hit the pond at all so I don't know if that will be okay for the plants to grow and the water to warm at all. Then again I don't suppose the frogs will be sunbathing