The Engineer said he did on the last 4 visits. If we mess with it our warranty becomes invalid, so I have dissuaded my husband not to meddle!!(Hottubs are very expsensive in the UK!) We did have look and the leak looked like it was coming from the light seal. However the engineer changed the seal and we are still leaking! and it's annnoying now as it won't heat up!! He can't come out now till the 15th Sept, so I am finding out as much as I can so I at least sound intelligent when he arrives, and can make sure this time he checks everything.
Thanks for your reply, this is the first thing I'm gonna make him check!