Ok, more nonsense ...
Decide to test fit anyway just to see if they worked, and the next problem came to light.
The length of the wiring with the 1157 plug is at least 2" too short. Due to it's position, by the time it runs to the housings plug-hole, it only just sticks out, leaving you absolutely no room to try an insert/twist into the standard light socket.
Might be possible for those with small fingers, but I've tried for about half an hour and still no go.
I then tried to fit them without the rear housing and I just can't get it to twist into the socket. Doing it by hand, the wiring is at risk of ripping out when I try an twist it in because there's nothing to grab onto, and using some sort of tool is a no go as the metal on the plug is just far too flimsy and crashes/deforms as soon as you touch it.
At this point I'm just going to take them to my local auto-electrician, have him sort out the
bending-of-the-leds, and also bypass the 1157 plug/socket and just hardware them directly into the wiring harness.
More money!