Sadly that’s not how your bodys internal clock works. It tracks 24 hours for sleep/wake pattern no matter if you go to bed later or rise earlier on a given day.Did they change the original schedule? Because I heard they were leaving after practice on Thursday.
I know that most people travel over to London at night, but I think traveling during the day and getting into London at like 10pm is the best way to avoid jet lag. You are tired from traveling and just go to bed once you get to the hotel. Use the time on the plane to go over game plane stuff with team instead of having guys try to sleep on the plane on the over night flight which is never comfortable.
General rule of thumb is it takes 1 day per timezone to adjust.
And sleeping meds are not really helpful as they don’t give “quality” sleep where the brain goes through its cycles to clean up.
Of course depending on the schedule (eg evening training sessions) and availability of blackout curtains the team might not need to adjust to GMT at all.