It seems a bit odd to me that CO are operating 2 x 757s/day rather than 1 larger ac as at MAN/GLA; I assume that all the 767s and 777s are being used on other routes and there was a spare 757 that could be switched to transatlantic flights rather than domestic routes.
I flew Continental to Houston back in Feb 2001. These were the options then:
1. LGW; Direct B777 to IAH
2. BHX; B757 to EWR then B757 to IAH
3. MAN; B777 to EWR then B767 to IAH
Guess which one I went for…not BHX even though it’s nearest to my home. The B757 is one of my favourite ac but I refuse to fly on one transatlantic. LGW is too far from home really and only 2 flights so I opted for MAN. On the return trip I deliberately chose a DC10 flt from IAH to EWR; great ac but very dated after B767/777.