put the pump and controller in a location where you can access them easily? I fitted plugs onto all my pumps and controllers with spares on a shelf ready so if one needs replacing (which is very rare) there is one on the shelf ready to be swopped and it will just plug in so anyone could swop it over. all connectors are fitted with proper crimp terminals (not bullet connectors, heat shrinked and the terminals dipped in silicone grease to stop the moisture corroding them, you could use waterproof superseal connectors
same goes with the split charging function, the Doblos that I have the older ones have a split charger spring controller, these work fine even with electric hose reel and rarely need bench charging, so ignore what some say about saying the leisure battery's need bench charging and a split relay not being enough, there are too many variables and my vans almost never need bench charging except for when one of the leisure battery's is weak and needs replacing.
The newer doblos I have use a battery to battery charger, easy to install, buy the waterproof version.
The reliability of the set up is down to the quality of the installation,
Combo van spring controller with split charge function
Spring controller connectors
Side view of Transporter
Leisure battery in passenger seat VW Transporter