The guide that R2D4 put together has been an invaluable resource; everything you need to order the genuine parts can be found there.
As I see you are in the UK, may I suggest that you get some parts from Cousins UK. They don't have the choice that Ofrei does, but for expensive things like dials, bezels and crystals, I recommend getting them from within the UK. I ordered a lot from Ofrei, but got hit for a hefty customs bill because they are declared at full value.
Good luck!