Rotherfly - why not try the City Unit test if you are going to be in the UK. £75 and they will give you all the tests so that you can see what you can do and actually try the Bayne.
The FAA light Signal Test (as I took it) was taken sitting in a car with an FAA examiner. This guy is NOT a Doctor but an FAA official. First we parked at 1000 yards from the tower and the FAA guy radioed the tower to start the test. You tell him the colours you see. The test was then repeated at 1500 yards. The FAA man was concerned that the tower had tinted windows and this would affect the test, but I passed OK - I'm not sure if they allow mistakes.
To get the test you must have an FAA medical with restrictions because of colour vision. You then apply to the FAA and they give you a letter to take the test. Sorry I can't remember the exact details, it was 13 years ago. If you pass you can use this towards any aviation medical.
NOTE: Even the FAA said that employers do not like the SODA waiver, but I know that jobs ARE there for the right people with them.
We all know how you feel here in this forum, but don't get down, do everything you can to fulfill your dreams.
City Uni is at :
http://www.city.ac.uk/optometry/publ...ourvision.html
Hope this helps. PM me if you wish and all the best for your future.