From here it could be KHS or NVS, last digit looks more like 'L' which would tie in with a Spitfire iv. Then again it could be 'W' or 'V'...
NH is Nottingham, but the poster doesn't say where it is. Whilst I was searching for that one, I found this one...
However the REALLY worrying thing given the current flooding situation in some towns on the mainland, is that I found THIS one...