Leave it to Britain to work hard at making Jedi a religion. I heard tell that many answered this on their census in regards to a religion.
I don't know that I see 'Jedi' as a religion but more as a philosophy, much like Taoism. It is composed of a code of behaviour that yes, was started by a Hollywood movie director but that has been expanded and that has been based on other "real world" practices.
I read their letter and I shudder when I read, " We have a proud heritage dating back 195,000 years to our first Jedi, the blue haired, blue eyed Kaja Sinis, who was born on Coruscant."
First of all, none of that is founded in reality-at least that we can measure. Second, the "blue haired, blue eyed" but sounded like greying Aryan nation members.
I applaud them for wanting more Religious Tolerance. I just don't know if they will be taken seriously.