Watch List notes:

Aethelstan (924-939), Penny, circumscription cross type, Hereford, Ecgbeorht, 1.66g, + aeðelst^n rex br -, inverted n, small cross pattée, rev. + ecgberht m-o heref, small cross pattée (Blunt {1974}, no. 176[b], this coin; N.671/2; BMC V; S.1093), light iridescent tone in recesses, a pleasing very fine, very rare.
provenance
Bagnall, collection dispersed by Spink (acquired 10 July 1964) - £34.10.0
Shand, sold privately c. 1949

Further reading: C E Blunt, "The Coinage of Athelstan 924-939, A Survey", BNJ, 1974, pp. 35-158
Estimate: £1200 - £1500