Thanks for all your advice. The 3A fuse and holder arrived yesterday, so I have attached it to the red wire:
My soldering is terrible, but I've tested the connection with a multimeter to make sure it works.
The power module didn't look waterproof:
To be confident of keeping moisture out, I've mummified it with self amalgamating rubber tape. The blue wire should be black, but I didn't have black wire:
Now that the connecting cable (from the kit) is in place, routing the signal from the cable leading to the display, to the power module, I can confirm that the two lights which are already attached via the cable for lights which exit the motor, still work when activated via the display; therefore it's a splitter - it doesn't hijack the signal. Now all I need to do is connect the battery to the power module.
My question is, can I use a normal 13A block connector like this, between the battery and the controller? It'd be easier to split the power between the power module and the controller using just a basic block connector, or should I get a 60A block connector? Or something else entirely, like this:
...or should I simply solder the wires together?
...or can I just use a couple of M6 bolts and nuts, and cover those with insulation tape?