Hi Steve,
(I don't have enough posts yet to PM, so replying here)
Yes, you are mad (: and so was I, but it was satisfying to be able to lash the thing up in the house, in the warm, running off a power supply from an old PC and without cutting wires in the car.
I reckon you've got the right choices there. The ones I bought were female, and duplicate the connector on the car, but if I understand your requirement correctly you need ones that plug into the car wiring, so 'male' in the terminology this supplier uses. The pins in the male connectors are recessed, and have a flat blade. The retainer for the male connectors seems to be in stock:
https://www.hi-1000ec.com/product/289
On the female connectors that I have, the retainer clips in at the back to stop the pins from being pushed out.
Another thought, though. What does the connector on your replacement radio look like? I have a spare of the Y connectors that I bought, terminated in (IIRC) an ISO socket -- two banks of 4 by 2 pins, keyed at one end, like this:
https://en.wikipedia.org/wiki/Connec...nit_in_car.JPG
except that on mine the two blocks are joined together; they could easily be parted though. I'm happy to send you that if it's any use.
Cheers,
Phil