there can be considerable evaporation at 35 degrees.......
Don't forget to regularly check the electrolyte level of your leisure battery, especially during a long stay in hot climates as there can be considerable evaporation at 35 degrees. It happened to us, when we disconnected from our hookup at Oliva on the Costa Blanca we wondered why the battery condition indicator showed a problem. 3.5 litres of water later we knew the reason. Thankfully the battery is now OK but it could have ruined it.