Went down to the motorhome today, have not been able to get there for a few weeks but was not too concerned as the solar charger was working well and batteries fine. Central locking wouldn't unlock from the fob so I let myself in using the key manually to unlock. checked the 12v system and both the habitation and vehicle batteries are virtually fully charged - watched solar charger working as well. All the batteries including the vehicle battery, are only a few months old. Tried to start the van as I thought I would take it for a run, and there isn't a flicker of life - zilch. Stereo also not powering on, no dash lights, no starter turning over, nothing. Where should I start with troubleshooting this? First thought was to perhaps buy a new battery for the keyfob but are there any other issues I should check before having to pay ££££ to get someone out to it? The van is an Adria Vision on a Renault Master chassis. Advice would be greatly appreciated.