Rails connect surface mount digital point motors with NCE power Cab

[nomis47]

I have 2 of these -

 

https://railsofsheffield.com/products/rails-connect-rpm-smd-1-rails-connect-high-efficiency-surface-mount-digital-point-motor-single-pack

 

connected to 2 x Peco points with both decoders set with the same accessory number as I need to switch them both at the same time, this works correctly as expected. At the weekend I added a single momentary switch so that i can manually switch them by just pressing the switch. This works for a few seconds and then point A switches back after approx. 5 seconds and then point B switches approx. 10-15 seconds later without me doing anything! I have double checked all the wiring but cannot find anything obviously wrong. It's as if the DCC accessory decoder setting is somehow overriding the manual switch setting. 

 

If I change the switch to control just 1 point it works as expected so perhaps I just need to have 2 switches?  

 

Alternatively maybe I should just use 1 decoder for both point motors but as they are 4 metres apart i'm not sure if this is too far or maybe it doesn't matter providing you're using DCC solenoid connection wire DCW-PW25 ?

 

My final question is should the points have their springs removed or not when using these decoders or doesn't it matter? I currently have 1 with and 1 without.

 

thanks for any help/suggestions.