hi people ive got a 2013 l405 sdv8 lovely car, the fuel burning heater works great, want to upgrade with remote, ive bought remote which is one with fan and heat rising for on, cant get it to pair, can anyone talk me through procedure from start to finish, thanks in advance.

I think you may have the wrong fob for your car.

If I'm correct, the later cars have Webasto heaters which use the fobs with the little heat design. The earlier cars likely have the Eberspacher heater which uses a different fob. You can check yours by looking at the heater under the bonnet (Google will help you with finding the location, it's fairly easy to see). Or you can look at the module in the D pillar, I think they say Eberspacher and/or Easystart on them if you have the Eberspacher heater.

Anyway, the process is:

(Optional step 0): Remove the battery from the fob for a while. Unknown if this helps if the fob is already paired to a car.
1. Pull the fuse (exact fuse depends on the car but it should be described in your manual) and wait 5-10s.
2. Put the fuse back in, then press and hold the 'OFF' button on the fob. You should see the LED light uo red for a couple of seconds.

This post contains some more info: https://www.fullfatrr.com/forum/topic57037-15.html