This is what the port looked like...Nothing is going to work in that!
After a bit of coercion with the soldering iron, the USB port came out. It wasn't a clean extraction but I got it out. At the same time I stripped and tinned the USB cable end.
Then it was just a matter of soldering in the cable where the old USB port was.
The reason I chose to use a USB type B cable is so that it can plug into my USB hub directly. Essentially it means that instead of 1 USB port my RPi now had 7!
So does this work? Indeed it does! Here's a photo of the RPi compiling a new kernel. So far I've not had any issues with this set up. WiFi works, USB storage works, keyboard works, seems very functional overall.