Obverse:

EDWARDVS REX ANGL Z FRANC. Facing bust in tressure of nine arches. Saltire stops.

Reverse:

POSVI DEVM ADIVTOREM MEV, CIVITAS LONDON. Long cross pattée dividing the legend, with three pellets in each angle. 

Good fine, toned, very rare. Only 10 other examples known, 4 of which are in museums. 

Ex Clarendon Collection, Part I, Bonhams Auction, 28 Mar 2006 - Lot 443 - (Realised £587.50 Inc. P.)

See D. Greenhalgh 'The Galata Guide To Medieval Half Groats' pg 43 No. 7.