I'm living in the US, but I managed to come across a tremedously helpful ex-pat instructor nearby who believes I can just shoot down to florida, get my CAA medical (there's a few approved docs around) and do a few hours at a CAA approved flight school (e.g. Ormond or Naples). My plan is to get my UK ticket revalidated then pop to my local FSDO and get a restricted FAA one issued on the basis of that.
If you aim simply to get an FAA certificate on the basis of your lifetime UK licence (though if one of the tan coloured ones you'll need to get the CAA to re-issue it so the number on it is valid) then you do not need to get your UK licence revalidated first.
When the FAA speak of the need for the underlying foreign licence to be current and valid they mean not surrendered, suspended, revoked, or expired instead of what we might think current means.
With your FAA certificate on the basis of your CAA license there is no need to satisfy the experience requirements of your UK licence as long as that license is not surrendered, suspended, revoked, or expired (which includes changes in the licence numbering scheme). You will, of course, need a valid FAA Flight Review (formally known as a BFR) to exercise the privileges of your FAA certificate.
By the way, to get your FAA certificate on the basis of your UK license an FAA medical is sufficient.
This is explained in Chapter 29 of FAA Publication 8700.1 which is available at
http://www.faa.gov/library/manuals/e...spectors/8700/
A question: would it be legal to fly in the UK using an FAA certificate issued on the basis of a UK PPL when that UK PPL was not current (in the sense that we understand the term)?