Indicators not working as should with my new Swift

Hi

I have a BMW X3 2009. I was informed that my hazard lights on the Swift van(2019) was pulsing whilst driving. On checking further i noted that my indicators were going really fast. I was informed by my caravan agent that i needed a VLM board fitted from Sergent of Beverley(they make the Command units and trackers for Swift Caravans). On fitting this i noted that with the ignition only on every thing works fine. However once i switch the engine on i get no indicators - those they are still flashing normally on the car. I am aware that my towbar is factory fitted and does not have a fridge/auxillary battery fitted in the loom. Does this make a difference. Any suggestions would be very useful as it appears to have everyone baffled.

Would a new UK loom fitted solve the problem or is it the caravan?

Bob Pattison