"Not much cop" - means useless, disapointing. It's a very commonly used expression in England. No idea where it comes from. Somebody round here will probably come up with an answer. (I tried an online dictionary of slang but it didn't have it.)

...

True, choruses are fun - but any number of wonderful traditional songs don't have any chorus. I suppose if you've heard them often enough you can sing along with them (though it's best to be careful about that, it's not always welcome to the singer or the other listeners).

"...maybe as people are more passive in their music consumption, especially if they don't sing, the importance of a good tune just becomes a whole lot less. I'd have thought it might work the other way round.