The only routes I can see this helping on is the ex outstation nightstopping aircraft on the first run back to LHR. JER/MAN wasn’t a problem as they got a bacon roll, but AMS/CDG etc that got a full hot was a little more challenging.
Because of the ways the trolleys are set up to accommodate chill boxes containing hots and fruit etc it makes it really difficult to configure them in a way that makes the service easy to deliver. The on the ground prep required to set up trays and trolleys etc is rather higher than when you’re just getting on an aircraft at LHR, or one that hasn’t nightstopped. This isn’t a problem on low club load flights but higher ones could be a challenge. What you often find was that crew wanted to cut corners (for example, by putting the hots in a box on top rather than posting them onto the trays in the trolley) in order to save time.
Of course this isn’t a problem departing LHR as you don’t have the issue with the chill boxes so it’s just a case of hots on trays and go, but some crew did still struggle with this for unknown reasons.