Hampshire Welfarer Ambulance.

This could be HAA 701. See next two photos.
Hampshire was divided into four areas Green (Lymington Stn and the New Forest), White (Fareham Stn and South East Hants), Red (Winchester Stn and Mid-Hants) and Blue (Aldershot Stn and North East Hants). Each area had it's own Control Room (at the Main Station) attached to which there were several sub-stations. Fareham, for instance was 'Hantsam White Control', which had sub-stations at Hedge End, Gosport, Havant and Petersfield.