I checked to see if anything was draining it as it took soooooooo long to recharge it from the mains last week.
A fluctuating drain of between 0.5 and 1 amp was registering on the hand held ammeter - even though everything was switched off

Finally traced it to the interior strip lamp - it's inbuilt invertor to power it up had a transistor fault and was pulsing continously, even with the lamp out!
It wasn't a huge drain but enough to discharge the battery over 4/5 days -gonna remove it and fit a set of Ikea recessed lights in it's place

If your battery (main or leisure) suddenly packs up it's worth checking out the light before condemning the battery.........