Hi David & Leanne,
I want to say Hi and to put in a comment about your batteries.
Frist, I agree with Bill that you should replace the lot. Second, I suggest a different replacement. If you can get them, and they are widely available in france and Europe, I have been very pleased with Calcium batteries (really calcium, lead, acid). The Calcium batteries take a much higher (and faster) charging voltage, don’t discharge when left for extended periods of time, and have a longer life and more cycles. They are usually sold as sealed, no maintenance batteries. I recall that mine cost about 50% more than a standard deep-cycle lead acid, but the long life compensated.
If you do go that route, be sure that the charging voltage is as high as specified. I was warned that if it was less, the batteries would not last.
Other than the battery problem, I trust that you are both having a wonderful time.
Miles s/y Ladybug, sm216, Le Marin, Martinique