Thanks to all those that gave assistance/advice on this.
We have success. 2 DPDT switches wired up to 2 controllers. And it appears to work - so even better ! I can now 'play' at shunting in the yard whilst I have 2 other locos chasing their tails - Brilliant !
Feel quite chuffed now.
Thanks again folks, much appreciated.
Cheers Mal Oz