ALKO-ATC

ATC will not work with a single 7 pin socket as it requires a permanent power supply. I am assuming that your caravan has a 13 pin plug and as such I would advise  having your T5 socket changed to a fully wired 13 pin socket then you will not require the adaptor.

Here is the ATC manual if you have not got one.

Agree with Vulcan, but also for your holiday trip you don't need to have the ATC working as safe enough if the vehicle and caravan are a decent match and you don't drive like a lunatic and take care. get the plug changed on your return. 

Thank you all for the advice, can't get the pin changed until next week.

The 12N socket you have on the T5 just provides power to the legally required lights on the caravan, the reverse light would be powered form the 12S (grey) socket if one was fitted, The adaptor you have used to plug your caravan's 13 pin plug into your T5's 12N socket just covers the road lighting ....

Note that if the caravan has a reversing light, then it must work, so it*s best to get the job done as soon as possible.

hardly the crime of the century if it doesn't ..... I can't even think that the reverse light on my car is ever checked at MOT time.

No of course it isn't the crime of the century and it's not even an item that falls within the scope of an MOT, but it is nevertheless a requirement. Obviously no need to interrupt a trip with the caravan to have it put right at the very next dealer.

I think any dealers car or caravan would  be the last place i would go to have the plugs changed ,it needs a specialist towbar company to have a reliable outcome

. 👍👍 

It just surprised me that anyone would even comment on the legalities on whether a reverse light was a requirement or not .... I have a trailer board that I bought years ago so consequently no rear fog light, I suspect that also falls foul of the law when connected to my towcar. 😉