LONDON Decca, Tzar DST and similar cartridges

@howardalex, a while ago there was some talk on this forum about 'special' FR7's with unbelievable specs. Very rare and perhaps aimed at the professional market, as you suggest. In any case, it appears you are in possession of something truly special! 
The FZ version is usually quoted as the best of the regular models, but I have come to prefer the MC 702. Another peculiar and rare one, apparently the last of the FR7's and supposedly aimed at the European market. Whatever the case may be, it is exquisite.

I’ve now listened to the LDR at 1.65 gms and on some of my (admittedly quite worn) 1960s Argo recordings there was some mistracking, so I’ve increased to 1.85 gm which seems to banish that 

Thank you @halcro beautiful song :) ! Cannot judge the sound on this one as I'm not listening pop/rock so no points of reference. Thank you also for the VTF setting, will try that!

HowardAlex, my tonearm must be better!

FR7 series I actually have the basic FR7, the FR7fz (that  you refer to), a “one off “ which is stamped “PW-1” as well as the FR7fc.
In my system the FR7fc and the “PW-1” shade it ahead of the fz (which is itself a big upgrade on the basic FR7). To my ears the fc is just more musical, like an mc version of the London Reference.

Of course my ears could probably also do with an upgrade, but sadly I’m stuck with them !

Interesting, I realized you have all the big guns already, great!  
I gave up on "fc" since i have "fz" (and "f" before). 

My current injection phono stage transfered my FR-7fz to another level, compared to conventional pnono stages, hedamps and SUTs.