E30 Zone

is there any difference between the spring kit for rear drums amd rear discs?

Yes.

any way of telling before i try to fit it, I have a kit here but I have no idea if it is for drums or discs

The drum brake kit parts are much beefier than the kit for disc handbrakes, which doesn't help all that much unless you have both parts to compare.
The disc handbrake kit should have two retaining springs and pins plus two coil springs with hooked ends.
Drum brake kit should be two separate kits for retaining springs and shoe springs. Retaining spring kit should have pins, springs plus washers that the pins pins fit into, and the spring kit should be three springs with hooked ends.

well there is four springs in this kit so I assume it is the correct one for discs,

cheers brian