Thanks for all the advice guys, this is very helpful!

I will definitely see if I can grab some VIP tickets for ExR Guildford next year so I can have a closer look at some FW's. I went to RoboGames this year hoping to do the same but it turned out they were middleweights (I mainly went hoping to see Last Rites)!

I'll have a think about starting out with something different, if I have time at the weekend I will see if I can design perhaps a lifter that down the road can be converted into a vertical spinner (Can you tell I like kinetic energy weapons?) later down the road when I'm more comfortable with how things work.

The only thing I'm really precious about in the current design is the shape of the back...it took me ages to get that right in SolidWorks!