[ROVERNET - UK] SD1 LH Track Control Arm - Where can I find one?

[pj.info]

Dear Rovernetters

Thank you for your answers to my message below. I went on looking for a 
replacement LH track control arm for my '86 SD1 but without any luck. So I'm 
coming back again. Any further hint? The part references are below.

Many Thanks for your reply.
Best Regards,
Pierre.

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Original message:
On passing the periodical technical check, everything was fine on my SD1 but I 
have been told that the LH track control arm is slightly over the slack 
tolerance, so that it would be fine to replace it. I tried to find it i.e. 
the LH/RH pair without success. The RH one does'nt seem to be an issue but 
the LH one doesn't seem to be available anymore (Switzerland, Germany, 
France, Rimmers, UK and Holland SD1 Rover Clubs, etc...).

Does anybody know where I could get a new LH one or eventually the pair?
Here are the Part Numbers:
CRC1423 (LH track control arm), also GSJ219 ?, also GSJ1104 ?
CRC1424 (RH track control arm), also GSJ218 ?, also GSJ1103 ?

Thank you for your reply.
Best regards,
Pierre.