gav008,
As far as I'm aware, the updated long haul service is being introduced as planned from 1st May. Whilst it won't be on the new aircraft, the service will still be rolled out as far as i'm aware. I'm told this includes free Tui snacks mid flight, all seats will have upgraded IFE, ie all passengers will have on-demand rather than looped, branded food and hot drinks as the second meal, branded coffee and hot chocolate (Starbucks) available for purchase on drinks rounds, premium club will get a revamped pamper pack. The amount spent per passenger on food will pretty much double hopefully resulting in better quality meals, although the main meal I find fine at the moment, it's just the second that's not always great but that should be addressed.
Since you'll be flying before me, maybe you can feed back on the new experience? The aircraft for your flight hasn't changed as far as i'm aware.
Darren