"Charles Lancaster Circa 1920 280 Ross-Eley, as supplied to HM King George V, HRH Prince Of Wales, HRH Duke of York."

Sorry for the English lesson but my reading of this is that the rifle was made for or at least supplied to HM King George V. This is either true or the seller has a poor grasp of English or intends the implication to be taken as true.

Kuduae's sentence in his post also means the same as the above.

In both posts the first part of the sentence describes a specific item, then "as supplied to or as used by .......

This is direct implication.

Nevertheless a nice rifle but in a rather poor cartridge and $28,000, he's got to be kidding.