Chinese pistols as you know had a number of manufacturers...but the is a company in the UK called Worldwide Arms, they source militaria all over the place and mainly deal in antigue and odd bits of hard to find kit. I hate to tell you this but nearly all of their firearms which would be considered subject to UK firearms laws are deactivated.
I know that they have had all manner of broomhandles including the Chinese and Astra variants in the past they may have magazines, it's worth a try and they will ship at a reasonable cost. I have had all sorts of stuff from them in the past, Lewis, Thompson drum mags etc.
Tel: 0 11 44 1785 851515