Ta mate. I am quite happy with the result, but it's taken for ages, they've set me back £280 and I'm only a school teacher (I'm not rich you see).

 my sister in law is a teacher too,but 5 years up i think.

 I do A levels but I am not currently working. I am having a gap year.

 I am still trying to figure out how to extract the countersunk shoulder screws to put the new one back in, but thanks anyway. I am really happy with it.

 Turn them with an Allen key sorry if that sounds obvious but that's how my switch ones came out.

 That's what I did, but they're shoulder screws which will screw just onto one of the sides and now I am stuck halfway through it. The countersunk socket in the carbon swingarms (metal tip where the holes are) has no thread in it has it. I can't pull it out after undoing the other side. Maybe there is like some inner ring or something blocking it. I think I am gonna take it down the shop first thing tomorrow morning. I know it is only a screw, but it is all going over my head.

 As you unscrew the screw the tension in the frame will release and jam the screw,try and align the holes if at all possible and gently wiggle them out.