Perfect, Ive just added one to the top of my design. My keen-ness made me read the rules too quickly and I thought I needed one on the top and bottom or at the back as it can invert. Thanks again.

I have lots of the Pololu 25D gearboxes here at work so was going to use them. I had though that this would keep things simple but now I am thinking of going brushless after seeing a few build vids online and having a lot of ESC's in stock. It would help with weight as until my blades arrive I only know their theoretical weight.

Any good UK suppliers or combinations of gearbox / motor that are recommended?