Constant speed.
Go do the ATP. I am an ex cadet with them. I fly a 757 for another UK charter operator now. I always wanted to work for Brits, but they just never came up with the goods at the right time.
ATP is excellent. If you do the course, just forget about anything else. Forget about Brits. If they ring before you join your airline, go to them. But I don't think they will.
I am pretty well connected in Brits...a TRI/TRE friend rang me today. He believes that when they do recruit in the future, that they MAY go for type rated 757 guys who are available and suitable before they go back to the un rated holding pool. It all comes down to economics. Of course they may not.
I guess what I am saying is do not wait. Brits are good, but so are the lines that ATP will get you in.
Expect a 737 course i reckon. easyJet maybe??
You have done extremely well to get in the ATP. It is tough.....but then again you are obviously quality as you got selected by Brits too. Enjoy it. I loved it.
Best rgds.