Getting pee stains out of light carpet

[PapuaNewGuinea]

How would I go about getting the orange-ish stains ot of the carpet in my flat?
I'm moving into my girlfriends flat in a week and don't fancy leaving my current flatmate with these stains. I've tried a foam carpet cleaner but it barely worked as the stains are quite old (I should have got them at the time, or laid something down, I know).
Any help would be appreciated

[cavyinhawaii]

I am not sure where in Scotland to get this but there is a cleaner that is enzyme based. Here it is called liquid alive- brand name. There are also generic names. I got it at a janitorial supply company. I think you can also buy it from professional carpet cleaners. It usually will have on the label will clean urine, vomit,and protein stains. You put it on the carpet and let it sit the enzymes eat the urine. I have found something simular at walmart on the vacuum supply isle.