Hard question that, Norwich was a far better facility, more modern and spacious with better support shops, also the interest of F27 and F28 maintenance, however a large part of the maintenance at Norwich was for third party customers, Busy Bee, Aviaco and others, therefore the costings and down times put pressures on the work.
I enjoyed Blackpool, also Norwich which had the additional benefits of really good pubs, I would say 50/50.