For the first part of your question, I'd say that you did the correct thing and continued with final with my understanding being that the "overtaking" aircraft doesn't have right of way - especially in this situation.
At Redhill, I get the impression that there is a bit of an anti -microlight attitude in Tower which can lead to irritating problems on the RT. I had a situation the other day where I was catching up with one of the Shadows ahead of me and was given the optioin of orbiting from the Tower, I declined and had a bit of practice in slow flight instead which worked a treat.
I appreciate that your approach speed is pretty much a given but I can't for the life of me see why other pilots can't regulate their speed. I understand you may have more of a problem in a fast twin (or whatever) but why not make circuits more interesting and get some slow flying in as well.