British Airways have a basic fare which was introduced about two years ago that is cabin bag only and no free seat allocation unlike the regular fare which the majority purchase includes your 23kg hold baggage plus free seating within 24 hours of departure.
Yes and the non-basic fare is £20 more expensive per flight so you are simply paying £20 extra for a hold bag.
I am an Exec Club Member but still had to fork out a lot of money, especially on the long haul flights for the seats of my choice even though I was travelling in Premium Economy as I didn't want to be stuck in the middle.