Cheers ash.
It's fairly certain now that this frame won't be ridden properly for trials, as in I am not going to build it up and go do some drop gaps on it, it's probably going to be more of a wall ornament than anything.
However, to address what ash and BionicBalls have mentioned, this is my second year of level 3 engineering, so I am no way near an engineer yet. This is our first real project of the course and what you mentioned is part of the process of the project.
We have to produce a thick booklet to have on the final project day, it will contain our diary entries that we must do weekly about the project and also a shit load of other stuff. As part of the shit load of other stuff I will have what you two have mentioned, different material properties and different forces and the appropriate joining methods.
Cheers for both of your help though, I appreciate the time you've donated to my cause.
George
xx