Just to start the ball rolling - and you may get as many answers as responses with this being a very grey area in my view - I would suggest you do contact the CAA GA department. Their telephone number used to be 01293 573524. In my day, some 10 years ago, Bob Commander there was very helpful. Others may advise you to avoid contacting the CAA as they are regarded as 'the enemy' by some, but I feel that would be the safest course.
Perhaps someone who is more au fait with current CAA thinking on this type of activity can offer some further input here.
Good luck.