Thankyou everyone for all the useful advice and information. Please keep it coming.
I will collect as much information/ammunition as I can and then approach the CAA again. Whether that is by post or by appointment I don't know....
Part of the problem is that Joan Gardner who is one of the licensing policy people was very hard to get through to as apparently she is to important to deal with the public (a good attitude for a public servant). Given how totally non-committal she was I'm not sure who to try and deal with in the future when trying to get something a bit more definitive.
As IO540 pointed out I have also posted this on the Flyer forum
here. There is a fair bit of duplication but also some additional information that is useful and interesting.