[rick]

When you want to put that kind of prefix, you severely limit yourself to what will work for a channel name. Even looking at their current names, what they will become, and what they could be if they stuck with their original names, the old "UK" ones just look a lot better and the connection is obvious (with a few updates/additions).

W - U&W - UK Family
GOLD - U&GOLD - UK Gold
Dave - U&Dave - UK Comedy 
Yesterday - U&Yesterday - UK History
Drama - U&Drama - UK Drama
Alibi - U&Alibi - UK Crime
Eden - U&Eden - UK Nature
UKTV Play - U - UK Play

The "U&" just looks weird, and stupid. Sometimes you don't have to reinvent the wheel, it's already in existence and works just fine.

Now I'm not suggesting they should ditch the Dave brand, but if they insist on putting a prefix in, UK Dave just wouldn't really work and be as awkward as U&W is going to be, so better to use a more descriptive term for the channel.