Circa 1950 in Portsmouth, Hants, I volunteered for and joined 457 HAA Regt RA (TA); HAA = Heavy Anti-Aircraft. I left when called up for National Service.
In 2004, as a volunteer in Hillier Gardens, north of Southampton, Hants, I chanced to pick up a piece of litter close to the roadside. It was a formal, typed, Army Memorandum dated 22 October 2004, subject 'SIGNALS EQUIPMENT' from a senior NCO (named) in '457 (HY) Bty RA'.
Google tells me HY = Hampshire Yeomanry (I had first thought it meant heavy), started in 1998 as a close air defence unit, using missiles, based in Sothampton:
http://www.arrse.co.uk/wiki/457_(Hampshire_Yeomanry)_Battery
Also, my 457 HAA had been disbanded on 31 March 1967:
http://www.serfca.org/Default.aspx?tabid=122
ADDENDUM: I had kept the memo in a handbag I use in the Hillier Gardens for pencil, papers, tree label ties etc. In June 2013, just before I learnt of this website, I put the bag on the car roof and drove off from home. Some kind people noted it on the roadside, picked up papers which had blown everywhere, and returned it intact to my home.