2015 Berlingo Enterprise

[Onemanandhisrake]

Hi All new user,

I have a Berlingo Enterprise van on a 2015 plate.
I've just changed the locking mechanism on the rear barn door. basically I wanted a handle on the interior rear so bought the mechanism with the cable allowing for this.  
The lock is now fitted but these are the issues.

With no keys in the ignition when I close the back door it LOCKS EVERYTHING

I am getting the open door light when driving

It takes multiple presses of the key fob to get the back door to unlock

The van now LOCKS and UNLOCKS when pressing the UNLOCK Button on the key fob

I'm totally confused about the whole thing. I'm guessing it could be one of the following but any help would be amazing...

Sticky mechanism??
Electrical connector poor connection??
Central locking needs resnycing/reset??

Many thanks in advance.