Hi carl,
The only indication is the DIS saying lamp out, then it goes off again.
When I pulled in to the drive the other night the brake light warning was on (car driver side, not boot) so I used an old Naval engineers trick, tapped it and the lamp came back on.
REF: the rear licence plate, I swapped the lamps for LEDs. Previously I had a spurious DIS warning which came and went.
When I removed the licence lens I found the passenger side one was bone dry, but the lamp looked burnt out but worked. The driver side one had some water in it at some stage, the lamp connections were coated in white powder and the two copper contacts in the tail gate had a little darkening on them. So I cleaned the lamp holder and copper contacts. Greased all the rubber seals and screw thread.
After installing both lamps and holders, the drivers side one (that had some moisture in it) flickered then settled down. I have not scanned it yet.
Any thoughts, or is my car possessed.