As a long departed SNCO I'm astonished at what has come to pass. Supplier Partner? Core Catering Manpower? Geeze!
On the subject of combined messing, has anyone asked the erks how they feel about dining with a load of zobbits? There's a good reason for the separation of ranks in the military.
Maybe the right answer is to go back to the origins and have the Officers and SNCOs organize their own messes at their own expense, with public money only paying for the premises and a modest 'ration allowance' per head. As far as I can see there's nothing to prevent the mess members as a group, bidding for their own contract, then appointing their own managers to actually run the place. Any difference between the ration allowance and the actual service provided could be paid for as Mess Bills. The advantage would be that unlike independent outside contractors, the mess would be a non-profit making enterprise.
Just as it was in the first place.