So basically my head gasket went, while changing it I popped in some ARP studs, cleaned the mating faces and popped in a new gasket.
The new head torqued down fine, but when I torqued in a camshaft it snapped!!
My head is warped it would appear, I don't have a straight edge so I took a chance and lost; but I digress.

My question is:
>>As my MLS gasket has not been heat cycled is it safe to reuse assuming it comes off clean?>>

just because the camshaft broke does not mean the head is warped. did you torque the camshaft in the right order? you might have had a valve pushing against a piston. you are supposed to move the crankshaft so that none of the pistons are at the top. but if that is what happened, you might have to pull the head anyway because you probably bent those valves

i thought the 7a was non interference meaning the valves will never touch the pistons. so no bending.

>
This^

im not 100% sure on that. im just speculating on what happened

7A is non interference, and cams were torqued in correct order.
Considering the coolant level was half way down the block water jacket, I'd say the head is pretty toasted so there's a pretty good guess there.
Back to the reusable gasket question please xD

Short answer: Yes.