I have the Allon White heated seats, installed when Shaun made me a new pair of reclining/tilting seats for my 4/4. Very nice to use on a cold day, two settings, simmer and broil. Two subtly-mounted small switches (under dash to left of s/wheel).
We have heated seats in both our other cars, and have had them for ages starting with a Saab 99 in 1979! The Allon White seats do take a bit longer to heat up than those in our Volvo or Ford. I see there are now factory heated trad seats for £480 - seems a lot to me.
I'm sure you could equally well find a DIY option. There are some made for motorhomes (Dometic Waeco MSH200 about £150 and can be DIY fitted) that I was looking at the other day - these are for what is likely to be our next vehicle.
