Field Marshal the Duke of Wellington, a print of 1838

A print entitled Field Marshal The Duke of Wellington, K.G. &c. &c. &c. First Lord of the Treasury. Engraved  by Samuel Cousins from a picture by Sir Thomas Lawrence, P.R.A. Principal Painter in Ordinary to His Majesty, Image size 7 x 9½ ins within later card window mount with the old title cut frpm the margins and pasted to it, overall size 13½ x 17½ ins. Marked on the back as property of the Duke of Wellington RHQ but sold off with many other items after amalgamation. Postage in UK will be added. This item will only be posted abroad after removal from the glazed frame as glass does not seem to travel easily overseas. aug13/1

We have seen the print dated to 1838 but the reference to His Majesty suggests it was printed just before the death of William IV,