Well I've been to the battery man and yes its dead and he means dead. Turns out it's a remco brand which is apparently one of the cheaper ones. So we've replaced it with a full river which he tells me is one of the best and dearest available at $350 it will want be a better one. So I've got it installed and it seems to be working very well.
It would have been better if this post had been on the original thread, rather than a new one....
Make sure the charging parameters are as specified by the manufacturer.
If they are not correct it will fail prematurely. It will not matter if it is a good quality battery or not.