Well I was planning on growing some Lowryder this summer but have read that it's very easy for the plant to turn into a ball of mouldy sludge after a couple of days rain and since I live in Scotland that might not be too good. Are there any auto-flowering strains that aren't as susceptible to mould?

Forget about mould mate. Lowrider is just susceptible to being shit. Good luck anyway, you'll need all you can get.