Help- cat pee!!

[Chippy88]

I have just bought a second hand car (from dealer) and it was all good until the sun started shining the following morning and I can definitely smell cat pee in the car (I know that smell anywhere!!) We have narrowed it down to the back seat.
Does anyone have any recommended method of getting rid- I know it is going to be a nightmare. Seems to be lots of products around and also some home recipes but would be keen to hear of a tried and tested way.

I have not been back to dealer as assume they will not want to know.sold as seen regardless of pee!?

Thanks everyone

We used a solution of biological laundry liquid in hand-hot water to clean up puppy wee, and if you haven't done that yet, it's probably a good place to start. But I think you'll need a big of extra oomph to shift cat wee (yuck), especially if it's dried into the upholstery. Check pet shops for specialist odour removers, repeat applications, and ventilate the car as much and as often as you can to allow if to dry and air.