The finder of this hammered gold coin asked to remain anonymous. This is because the owner of the land on which it was found was worried that any publicity could lead to trespassers pinpointing the site.
The coin is a London quarter noble of Henry VI, of a type listed in the Standard Catalogue as number 1810. It has a small fleur de lis over the shield on the obverse and in the centre of the reverse. On the reverse there is a cinquefoil after EXALTABITVR, an annulet after In and on both sides the mint mark is a large fleur de lis. In English Coins 1180-1551 Lord Stewartby lists the type as IB on page 322.
On the obverse of this quarter noble one area in the legend is flat and there is weakness in other areas but the central part is VF. There is another flat section in the reverse legend but this side is otherwise in VF condition. If I was cataloguing this coin for sale at auction then in its present state of preservation I would set the pre-sale estimate at £480 to £550 and would expect the hammer price to be within that range.