motorwise wrote:I get the wife to do it

I think you may have missed the window for this one, you need very hot weather. I take them out, get some really cheap washing up liquid (up to 15p!) cos it's thin, and a buket of water a cushion (ie, 2 X buckets for a drivers seat, 4 X buckets for the double passenger). On the dry driver's seat, drizzle (cooking term!

) the washing up liquid over the bottom cushion, don't use too much. Then using an uplostery or medium scrubbing brush, spread it over the cloth of the seat and scrub it in. Dump half the bucket of water over it. Scrub it some more, then rinse it with the other half. Put the seat on it's back, and repeat the process. Leave it to drain, and repeat the process on the passenger seat. Use a whole bucket of water on the first process on the seat (sitting) cushion, rinse with a second bucket, tip it on it's back and repeat again. Now leave the seats in the sun, BUT make sure somebody can't nick em!!
You need a very hot day, as if the seats don't dry quickly (a day), they can start to smell musty. If you have one, suck some of the water out with a wet and dry vac.