If it's anything like mine, a clone so possibly differing in detail, the spring is awkward to fit but does stay in place.
Without traipsing back down the garden to examine it in detail it is retained at least as DC31k suggests, when rotating the handle in the usual clockwise direction.
I think it has some sort of positive engagement; and I have certainly not needed to crush it or cut bits off it; let alone try to make a "better" one. You'd need suitable spring material anyway, not an aerosol can base!
I think your first course of action is to ensure it is the right way round, engaged properly, and you turn the handle in a consistent direction, normally clockwise.