Hi all,
Thanks for all the replies. Just to clarify - the batteries themselves are fine (as far as we can tell), but once the sun goes down and the solar is no longer topping up the batteries the charge in the batteries is used through the evening on lighting the boat, keeping the fridge on, use of the water pump for washing etc. By morning we still have charge but not quite enough to have the light/fan on in the bathroom, the shower pump and water pump going to shower 2 adults. During the summer we had no problems whatsoever, we even ran the TV on the inverter for a few hours as well as all the above.
We know we're not getting as much charge now, and as someone pointed out as liveaboards with only one solar we knew we would struggle, hence the need for a charger to top up as well. We did look at Sterling but were advised against them because, apparently, they don't play happily with our solar charge controller. Victron has been mentioned to us before, so we'll look at them. We were interested in how more experienced boaters managed it. Some great suggestions coming back, so thank you.
Good to know it is okay to have both solar charger and 240v charger connected to the batteries at the same time. Wasn't sure if the different charging algorithms would try and compete with each other or something.