I've just blown the fuse when I installed the RGB mod (due to bad/insulating placement), could I replace it with a 1.5 A pico fuse? Or am I then just jumping the sha.., fuse?
You need to replace it with the same value and type of fuse, whatever it was. You should not put a fuse with a different rating or type into it. You want the same behavior from your replacement fuse as the original. Unless you are sure a different fuse is going to behave the same way, you shouldn't use it as a replacement.