SEARCHING FOR so-called BARRED NUMERAL LONDON-cancellations

[Olaf-SF-covers]

Espc. Mr. John PARMENTER and Mr. DUBUS WERE DESCRIBING THEM in details - mostly of them are so-called DUPLEX-cancellations (eg District offices/Branch offices). I really have a lot but there are many variations that are missing here. I am collecting them on (cheap) stamps but better is to get them with the 2-part-cancellation on cover/postcard resp. on cheap postal stationaries! By the way: Some types are (what I call) "SIMPLEX" - some of them are rarer than the DUPLEX.
If you would be so kind and inform me - then we can get in contact for mailing me a scan (or more) of what you maybe have to OFFER. MANY THANKS!
BY THE WAY: I am a collector from GERMANY.
Contact: Olaf.Groth.N@gmail.com"