[bazh]

It is so annoying because for the first time in my life I have really good compost

Urine is an excellent compost activator and if there's one things rats do well it's pee!

[AlaninCarlisle]

I don't have dalek-type bins, just enclosed wooden bottomless "boxes" about 4 ft x 4ft x 4ft. Every time I empty a bay I find evidence of rats' or stoats' nests in it such as dry leaves etc. I just treat it as an inevitable consequence of rural life. I suppose you're more at risk from them peeing on your crops than from anything they leave in the compost

[tallulah]

I had rats in my dalek bins and it was so off-putting I got rid of them!  We were overrun by rats at the time, having hens in a small country garden, and I stupidly didn't think of putting them on slabs!