I contacted the rifleman.org site about this.........got a comprehensive reply very quickly which I will put below.......top guys, and a brilliant website if you are interested in all things BSA / PARKER HALE etc.

Site is here;

http://www.rifleman.org.uk/BSA_sight...ccessories.htm

Reply is here;

Dear Edward,
it's their "CLOSE UP" stand, introduced circa 1950. It's in their 1951 catalogue, but not in the Post-War 1947 edition. For the reason your scope is labelled Parker-Hale read .....

http://www.rifleman.org.uk/A.G._and_...rker-Hale.html

Alfred Parker ran his firm separately, but sold many of the same articles as did P-H, indeed their catalogues were all but identical in most repects other than name, and P-H carrying a slightly greater range of goods.

Yours sincerely,
Terence Smith,
p.p. HARC-MCRRS