So with the help of @Diddums, @crispymorgan and @Mikepjbell a few nights ago, the PC is nearly there.
The PC booted up third time lucky after putting more power wires in and now just need to get a usb, then get OS up and running to finish the job off.
I'll have the USB by today so hopefully by the end of the weekend it'll be there.
Just excited to have it up and running tbh!