The most important part you need would be the windage part conplete, incl. threaded rod if broken.  Now, while some parts will be different, you might be able to get something workable using those parts from the 7A - so it might be worth the try - after all, it's not that the 7A's are that expensive.

I bid on the sight but was out bid and did not get a message to that I had been out bid until five hours after the sight was sold.  That was an excellent price and sight and I was willing to go much more.

Still looking for a PH7A sight

Early in this thread Gert was looking for sight inserts.
Gert; If you could post a sketch of the inserts you need, including diameter and the position of the locating lugs, I may be able to help.
Fred

Gert: In my box of sights I have two that appear to be PH. They have no numbers.I am sitting looking at 18 inserts of two distinct types:
Type one have two opposite lugs, not quite centred and one lug is wider than the other. Dia is about 17mm.
Type two has two centred opposite lugs of the same size. Dia is about 15mm.
If either of these will work, send me a PM with your address and I will post them to you.
Fred

Had similar problems with my 12/15 sight--no one in USA fixes. Fultons of Bisley is a possibility. Bob Adams (You need to Login or Register to view media files and links) lists several sights for other BSA models and might be worth an email. Good luck