exit rows free to select on short haul , paid on long haul
no free seat select available on HBO

There is no price banding.

FRom the BA website :

Members of the Executive Club and other oneworld frequent flyers are able to reserve seats at different stages, depending on their tier.

Tier Seat selection
Gold/oneworld Emerald Free seat selection from the time of booking
for everyone in your booking and friends and family on other bookings, who are travelling with you in the same travel class and on the same flight*.

Silver/oneworld Sapphire Free seat selection from the time of booking
for everyone in your booking*.

Bronze/oneworld Ruby Free seat selection from seven days before departure
for everyone in your booking*.

*You must be travelling on the booking (or in the case of Gold Members, one of the bookings) for these benefits to apply. They apply to British Airways flights only and are not available on Basic (hand baggage only) fares or group rate bookings. Exit row seats are not available to Silver or Bronze Members on long haul flights until 24 hours before departure. On some occasions, exit rows seats on short haul flights may not be available in advance due to operational reasons.