Leisure battery won't hold a charge (even disconnected)

There's always some "surface" charge that gives an initial high reading after charging before dissipating. Leave it for a day and read again.

 

Cheers Zed, I've never got this interested in batteries before. I'll see what it is tomorrow

 

it should settle at 12.6v when the surface charge has dissipated

 

HI , if u have a Bentley manual? you could do that test in the maintenance section ,the one where by using your multimeter you test each cell in turn to observe (perhaps obviously?) each individual cell charge which must not , 1 hour after charging be below a set level>one more indication of batt. condition>re multi meter accross batt. term? it does not indicate how fit for purpose batt. is , simply indicates a potential diff. as other fellas have said , got to load test it>AND, if u need to get another batt, if not getting a trade in deal get u/s one back >scrappies round here are paying £3+ per unit!hope this helps