As an aside to all this, if there is such a thing as an olde tyme parts factor, maybe taking in an old switch and asking if the can have a root thru their hopefully large stocks and find on that satisfies the crucial dimensions and fitting method, but is made with a right angle connector, which could then be made to fit. If the bayonet only goes one way, (there is a tang on it but it may have 2 recesses in the mounting plate 180 degrees apart, which is not possible to see so would need to be sorted by feel) then plugging connector in before turning and locking into position.

BITD there would have been paper catalogs with drawings and dimensions in. Luxury!

Communicator- you refererred to a 'slot' behind your switch, I did not have this to contend with, just an angle on a cross piece that angled down towards the connector plug. That was in retrospect a pain but able to be dealt with without surgery or bending the bracket as I was first inclined to try. I don't know if my pic shows in enough detail? I would have thought it being Fiat structure, it was the same. Never mind, 'tis dealt with now on my wagon.

The MoHoFun post seems quite grim, vehicle being stopped because of said switch. Really? I could maybe now help the guy, but the forum there wants me to pay to be able to reply and as the free site is read only, it is not helpful to paid members in a hole. I have had this before where I could have helped. It seems too that it is mostly a social thing for cliques to natter on!

For "slot" please see photo. I am not pleased with the standard of my filing, to the right of the switch in photo, but it worked for me.

Haha! It looks all too familiar! Was it only yesterday.......?
Indeed it was. It is identical to my set up, I see where you filed it. It doesn't look that bad, you are too modest- remember just how bad access is, and take a crumb of comfort.
As I said, I would be able to cope now, I believe. If I had been as badly stumped as I thought I was, I could have broken the old one off, it occurs to me, and just used heatshrink insulated spades on the new switch, and as long as they fit well enough I reckon it would be Ok. I have had a look on the Intermotor online catalog for stoplight swsitches, and there are lots that only connect with plain spades, and even come with them.
IMHO IO think I should present you with a 'virtual medal':worship: for your kind help, and filing under duress! Cheers!!