So I used the hair drier, and got the motor unit apart
All 4 solder connections on the switches were slightly cracked so I resoldered, popped the motor unit back in, took her out for a test drive.....
Made no difference, lights still do the same thing :s the motor works, i tested it, the switches are now fixed, the rattle only seems to be coming from the balance valves now too.
Officially stumped!
Also, noticed at night that when the red led's go out when I plant the throttle, they flicker very very slightly (as in so dim you can only just see them do it when its dark.... normal??)