You're absolutely right about the coat length - you can see the chalk mark on the skeleton baste near the hem to lengthen by about 7/8ths of an inch. I think they did lengthen it but perhaps it could have used more. I have a longer (yet fatter0 body in relation to my legs than many people.
That's interesting about Practical Tailors - I'll see how YWY's effort turns out and will pay more attention to their cloth books. I think I might end up with Chan because my real needs are a new dinner jacket, a couple of double-breasted waistcoats and new high-rise 'spongebag' trousers for morning dress and some more relaxed odd jackets and whatnot. Even though they'll probably cost a lot I get the feeling that Chan are the people best equipped to deal with these slightly unusual pieces.