Ok, I have an update for whover's interested.
I'd probably do it this way again, but I laid them all out on the board, taped over them, and then turned it over to solder, removing legs as I went.
I got it onto a tiny space, about 5x5cm or so.
Then I found out caps have polarity and I couldn't figure out the direction without the legs
Put it to the side for a while after that. Then I found another way, the stripe on the side, and was
I used solder to make the connections underneath (very tricky for me, it ended up being a bit messy, and I probably used way too much) and some jumper for the ground connections, which go to the outside, with the 5v running through the middle.
Then I wired it up to the expansion port using some coloured wire.
Then I soldered together a scart cable (also very fiddly on the din end, ended up melting through the plastic when a pin got too hot) after that, I was nearly done. Everything was wired up, I'd been soldering for several hours straight... and...
Nothing.
Took the multimeter to it, which was more difficult than necessary given the shortness I'd cut the wires to, and I couldn't get a reading from the live (using the ground on the circuit) so it's probably my crappy soldering which has cause the issue.
The next one I make, where I need an "L" connection, or even the 5v all the way through, I might just save a leg ot two and use them as the conduit. And the jumpering for the gound is messy and adds height, I think I'll loop the wires over rather than keep them under.
And the size is fine for fitting in a white PCE thanks to the size difference from the RF to the mini din.