I understand the Electra is based on the cycleparts of the James/Francis Barnett range,
so the stand is likely to be common to the Navigator/Electra/Jubilee . (?)
I had a FB in my yoof, and it had a cobbled up centrestand made from what looked like small bore waterpipe !
Quite well done and easy to use, but I don't think it was oem ?
I've never seen mention of a supplier of them, and what happened to all the original ones taken off by would-be
cafe racers has always puzzled me ...
All I can suggest is you take a tape measure to bike shows, and discretely take some measurements.
And keep a beady eye out at car boot sales.
Good Luck.
Pic selected at random