Delbots setup

Im trying to pin down an intermittent problem with a set of pro 120s running through a delbots interface.. The setup used to run in Thor.
Ive found a set of delbots instructions on the wayback machine, and they say that pro 120s need to be wired as below:
Pro120 ONLY
Our interface board connects directly to the Pro120 6-way
plugs with the exception of the +24V input. When using
Pro120€™s, Pin 6 on our board must be connected directly to
the +24V battery, not to the 6-way plug on the Pro120.
Interfaced Board Pro120
6-way plug 6-way plug
Pin 1 Connected to Pin 1 (F)
Pin 2 Connected to Pin 2 (E)
Pin 3 Connected to Pin 3 (D)
Pin 4 Connected to Pin 4 (C)
Pin 5 Connected to Pin 5 (B)
(Pin6 (A) Not connected)
Pin 6 Connected to +24v from Battery.

Now the set I have run straight cables with no +24v on pin 6..
The setup obviously used to work in Thor, but Im wondering whether its this that is causing the erratic malfunction of one board..
Anyone had any experience of delbots and pro 120s
?
I have a spare Quasar board I could use but I really want to pin down the fault rather than introducing other variables..

I have wired up the speedos and interface as above, running +24v to pin 6 on the interface and so far no problems. Ill try the setup in Carrot during the week if I can.