Right!
I spent most of yesterday afternoon underneath the MH trying to sort this problem out.
Firstly I thought to check out one of the rear LED indicator clusters as it has some small external damage due to my incident last year in Italy. There were some cables visible underneath but they looked good. I also unscrewed the LED unit out and the connection was sound to that. I also managed to remove a small piece of panel underneath the MH to access some more of the cabling but it al looked good.
Next I traced the clicking sound to the Sargent VLM5 LED control unit which was in my garage. I checked the plugs were connected properly in there and then started to isolate each plug and time the clicking noises to see which (if any) plug helped the problem. By doing this I identified 1 plug so then traced that back to the EM40 floor
fuse box behind my drivers seat.
I then removed the corresponding plug in the EM40 which was basically the 2 wire power circuit to the rear VLM5. Job done!
The clicking has stopped but I must remember to put the plug back in when we are travelling as it controls the rear LED's.
I have emailed both Sargent and the dealer who installed my new EM40 in November 2022 as this is now the second thing wrong with the EM40 on this trip as the plug/socket for the fridge control burned out a couple of weeks ago. I have had a response from Sargent on this and will update with some interesting news from them in due course, when I have had replies to yesterday's emails.