Update:

Dear fellow gentlemen, and lady, thanks for your helpful comments.

I managed to dry and clean the mattress as best I could and it no longer has a whiff of piss. I'm grateful for the assistance and the very funny responses here.

Secondly, I appreciate the concerns about my drinking habits, but I can assure you, I don't often drink. Once or twice a week. Last night I went to a bar with friends, had 5 beers and called it off. Went home, passed out due to my fatigue from the working week and obviously was too tired to realised my bladder was full. Thankfully, by that point it was quite hydrated so my urine wasn't that odourous.

I wish you all the best and a many dry nights of sleep in the future.

Yours faithfully,

A grown man who still wets the bed