Hi Chris. About the owners manual, I asked the same question last week I think it was. Well, something similar but the answer you want is in there too. The owners manual for UK, US, Euro and Jap are all the same just translated in to the relevant language.
As for the boost gauge, I never had it out but if you pop it out you 'may' find it has a back light bulb actually in it but it may have gone pop and need replacing. Cause you may not.
To check you'll need to pop the back off the sealed unit, just becareful not to lose any bits! I seem to remember that there are usually two little screws holding the unit together.
Hope that helps a bit mate.