Okay, I think I have a grasp on what this is now... I am still checking but the original post was partially correct.
The clothing industry in Britian had three elements imposed on it during the war:
1) Rationing -- this was regulated by a points system, so a dress was seven coupons, a coat 11 coupons etc. Every person had to surrender the set number of coupons along with the purchase price to get their clothing.
THe problem howeve was that a good quality dress was the same number of coupons as a cheap dress.
so
2) The utility label came along, famous for the CC41 tag, which although it means Clothing COntrol 1941, or Civilian CLothing 1941 (nobody seems to know for sure) the labels didn't actually appear in any garment until spring 1942. This standard was to ensure a certain level of quality through fabric and price control through government imposed regulations on manufacture and distribution -- one hair short of a nationalized clothing industry. These garments were sold without purchase tax to promote them and they were well received. They were also rarley identified as to whom the maker was. This was intentional so as not to provide an unfair advantage to the manufacturer since some clothing firms had been requisitioned by the government to make things other than clothing. THere are exceptions to the rule, such as hosiery, which continued to be marked as ALL hosiery was produced according to utility standards. However, not ALL garments made in ENgland during the war were CC41. Even though the majority were there were still options to purchase bespoke and non-utility garments, however, price controls were less rigid and purchase tax had to be paid. Utility is not austerity, in fact, it is almost the opposite -- it guaranteed a certain level of good quality in design and fabric.
3) Austerity measures were inflicted upon ALL garments made in England, whether they were utility or not. Austerity is what defined the number of buttons, pleats, lack of cuffs on trousers etc. and these were independant of utility, introduced in 1941 and 1942, with rescinding of certain elements of austerity in 1944 and afterwards.
So, my feeling is that the dinnerplate utility mark is probably a posh label but not for export. It denotes the garment meets austerity requirements but is not a utility garment because it is better quality and is subject to purchase tax.
I don't have proof of this yet, but from what I do know, and can figure out and read between the lines of official documents that I have tracked down, I think this is the best answer so far.
SO yes, I think it is a posh label that meets austerity restrictions but is not a utility garment. Often these garments appear with a maker's name as well, so that adds to the evidence that it was not government controlled utility wear, unlike most CC41 garments.