Following this post I bought a dolphin deluxe 4. It seems to do a much better job at actually cleaning than the polaris p93 which I had for 2 days before I returned it.
The only thing I am not happy with is that it doesnt seem to pick up the leaves stuck at the bottom. the leaves are too big for the vacuum slots and they just wont go in.
Also the bag is a pain to hose and clean the polaris type basket seemed more practical but again the thing wouldnt climb a wall even if I pushed it into it!

Overall a satisfied owner