Richard Lyon is the finder of the coin pictured here. It’s a groat of Henry VI, which was struck at Calais during the annulet coinage. In the Standard Catalogue groats of this type are listed as numnber1836.
The king’s face is slightly weak and there is a small crack in the edge between the letter I and C of hEnRIC. The obverse is otherwise about VF and the reverse a full VF.
This is a nice looking coin but is an example of a denomination, reign and type that turns up fairly often as a detecting find. In its present condition my price range would be £100-120.