CHARGING OPTIONS T4

Just wondering what options you guys with a T4 or other were using out there for long term charging of the vehicle battery during winter.
I already have a small solar panel on the dash for the leisure battery which seems adequate, but wanted a more hands off, rather than a permanent 12V charger under the bonnet with croc clips.
Thinking about a larger solar panel on a low garage roof which ironically faces south, with possible leads down to a connector, off to the "wired in" leads fitted on the battery.
Shame they didn't fit an inbuilt charger into the vehicle on the build phase back in the day, would have been the icing on the cake, or utilise the Commander caravan socket on the side of the Trident series of vans, parting ways where it draws Mains supply when on sites!!
Any other variations out there for simplicity of charging the vehicle battery?

Don’t forget the solar controller between the panel and the battery.

Yes Roger that, certainly need that. Any experience in the larger units specifically for this van?

Moving away from Solar for various on site reasons.
I know this is an early 1991 Trident, without any way of charging the driving battery for long periods when the van is parked up using the hook up lead like the newer vans, but has anybody fitted an inbuilt/onboard 12V charger working through the hook up 240V waterproof lead as used on sites for just mains?
If so a make would be helpful and where you stowed it please.