Watch List notes:

(g) Proof Details | George V (1910-36), Proof Five-Pounds, 1911, edge milled, 39.97g, 1h (W&R 414; S.3994), scratches in fields and on portrait, otherwise brilliant, a presentable example of this hotly-sought after type, in NGC holder, graded Proof Details ~ Cleaned (Cert. #5878609-002).
https://www.ngccoin.com/certlookup/5878609-002/Details/
Estimate: £4,000 - £5,000