It is my understanding that the WOF is a much stricter test than the MOT, with more detailed checks and held up as a standard to which other testing schemes should aspire - obviously there are some things which are slipping the net for whatever reason.
Reassuring for Peter will be knowing that his car has been completely checked and any issues sorted, another reason for restoring your own car so you know what has been done, those buying cars that cosmetically appear very sound, as this car did, may find similar problems in future.
I quite like the idea of a copper car brazed together though - we must have enough spare bits of copper in Keith's plumbing kit to make up at least a small vehicle
This is either an argument for the MOT being pointless, because a garage couldn't possibly find a lot of the critical stuff in the time available for a £50 test, or a much more rigorous test every X years where key areas are checked in much more detail.
Jack.