In fact, Sabre crews were operating the 737s, ex Britannia, at the same time that Sabre were operating its own 727s, ex Dan Air. I believe they were there till the Company was UK launch customer for the 737-800 NG in 1998. The aircraft were operating solely for one tour operator and were not the most serviceable around. They were registered G-SBEA and G-SBEB if my memory serves me right.