Problem with internal electrics

Hi
Can anyone help us please?
Have fitted a new, fully charged leisure battery today, together with a brand new earth strap, but the lights, water etc will not work, unless the ignition is on in the cab. The camper battery is fully charged too. 
Everything was working fine before we took the old leisure battery out. We’ve checked the fuses, and everything will work once we turn the ignition on, but not if we turn the ignition off. What has happened?
Thanks

Hello and welcome to this most friendly and informative forum. Advice will surely come your way very soon. 

So your leisure battery though new is not able to deliver it's power to the lights and water pump, whilst when you have the ignition on (motor running?) things are then powered? Fuses OK, so consider, faulty relay, faulty master switch, fault wiring. You need a voltage meter to track back from the battery's +ve.

A wiring diagram for your vehicle should probably be available for download from A-S in this manual. Armed with this you should be able track back to where there's the fault. Good luck.

Thank you everyone.
We’ll get an auto electrician to check, as we haven’t a clue. Just thought it may have been a simple fix, as the lights etc were working with the old leisure battery.