just noticed both the heated seats are not working checked the fuse that is ok seems rather strange both are not working, anyone any ideas on this ? not checked the relays but would be rather odd that all four relays have given up the ghost.

That is odd, has to be a common connection, such as power feed or earth....worth starting at the switch(s) and working back from there until you find power feed

Also, is there a link between the heated rear screen or heated mirrors, do these work as they should?

not checked rear screen or heated mirrors as yet i can understand one relay packing up but not all four i'll have a play and and see what i can find.

The feed may come through from the cold weather equipment

checked heated rear window fuse under bonnet thats  ok and tried to get the relays out from under drivers seat, and what a game that is even with seat in its highest position with the relay loom uncliped holding the plastic clips in just cannot shift the relays think i may unbolt the seat and tip it back so i can get more room to shift the wretched things, its possible they are frozen in the sockets.

It could be water ingress that's seized them in place?
Could also explain them all failing at the same time (if that is the case)

dont really think water ingress getting to were the relays are situated!