My Troll lives in a storage yard and I have nowhere to charge a battery at home so it is impractical to remove it between trips. The battery tends to go flat between monthly trips and is now not holding its charge at all - previously it would revive, but no longer.

The battery will be left in the van over winter and will probably be in a very poor state at the beginning of next season so I accept I'll have to buy a new one next year.

Is there a leisure battery available which is able to survive this kind of abuse?

AGM (advanced glass mat) batteries will stay charged for longer than a flooded lead acid (normal type). It is important to charge them fully before storage. Probably best to also disconnect the battery before storage. You would need to correctly select the battery type on your charger. They are fairly sensitive to having the correct charging voltage and also cost more (of course). I think that they can also be discharged to a greater degree than normal lead acid batteries.

These seem quite a reasonable price ( but I can't recommend them).

https://www.alpha-batteries.co.uk/12v-xt...AyABEgLUpPD_BwE

Get yourself a solar battery maintainer / charger.......do a google search.

We had 2 caravans over a period of 17 years, the first we boughtva battery for about a year before we sold it, the second our Eriba came with the battery and we sold it with the same battery working perfectly after 9 years of ownership, the 3 above batteries were probably lead acid and apart from "checking levels" they were'nt fiddled with, have any other sort of charger except the van makers installed system, and both were left out in the cold without a cover, one spent 4 winters in Northern Germany. I can't offer advice but just my experience, you have to remember this is before movers (as we were taught and knew how to reverse) apart from lighting, water pump, a microwave running through an inverter and a 12v music system there was very little draw on the battery, we also carried in the first van a Honda EX350 generator, again this was seldom used and we still have it nearly 30 years after buying it, works perfectly