I do not mean to step in where a certain REME Captain might provide a more definitive answer, but the Britishtests results showed the front loading on the barrel gave the best accuracy results off of a rifle rest. Not sure off of what soldier hold tests were done, but I seem to recall the UK test results were replicated twice. That said, from a competitive shooter point of view, using either the US single point sling or the UK 2 point sling the center bedding seems to give the best results. The chief difference I noted was the degree of sling tension does not seem to have as much effect on zero or rifle zero movement as the rifle heats up.
Now this might not be that big a deal in UK shooting, as with 2 to 3 shooters at a firing point the time between shots is on the order of 1 to 2 minutes. But in US shooting, where the shooter is on his own, often times if the conditions are the same you might be shooting as fast as possible, or around 25 to 35 seconds between shots in a 22 round string (2 sighters and 20 shots for record). In shooting a number of rifles side by side, front loaded and center bedded rifles, it seems the center bedded rifles hold zero and seem to show less deviation relative to minor changes in sling tension than with the front loaded rifles.
I will say that a lot of things competitive shooters prefer are not absolutely applicable to service rifles and how they are used under service conditions.