I was advised by my TA that i had to book M class for a MAN-LHR leg in my CRWSTAR on BD because there is no business class on domestic routes in the UK. M class on BD seems to be a "standard" fare and falls into the "regular economy" group.

I've since learnt of "premium economy" booked in Y i think, and it's found on domestic routes. I'm not sure what the difference is to "regular economy", and i don't think it's much to shout about, but at the very least, shouldn't I be entitled to it on a CRWSTAR?