It is up to date and generally deals with more modern components and equipment.

it covers a wide variety of components from modern bits to older items showing pictures of differences for the rest of use, who may get confused with the various bottom bracket styles available for instance. or types of hubs it is really a completely comprehensive book covering components so it should relate to everything on a bike old and new.

There's only one Blue Book. It is the second edition. It is written and printed in the USA and they may use different terminology.

This is from an American company and yes it should be edition 2 as it is a complete updated version of the original,

Not sure if there's any such thing as a UK version. Aside from the dubious US spelling (one day they'll find that missing 'i' in Aluminium) it works fine, since Mr Shimano and Mr SRAM don't vary their products for the different markets. You might need to do some simple maths for torque settings if you want Nm instead of in-lbs or ft-lbs. But otherwise it's a pretty universal book (and a good companion to the Haynes manual)