Poor charging can ruin even a good battery and most caravan 'chargers' are infact 12v power sources with a secondary use as a poor battery charger!
However and mostly, leisure batteries come in two physical sizes and we take it one is 85Ahr and the other 110Ahr, while this should be true it seems we've been seriously conned for years!! but no more.
Come September all batteries must be correctly and truthfully labelled and this includes their true capacity, all the good manufactures have already changed over.
Now it may still say xx110 but it won't say 'Ahr' after unless it is, beyond 110 it will perhaps state it's '20 hour rate' which is a bit confusing, good batteries though are more likely to be up front with the truth and state clearly the Ahr rating in Ahr's!.