Split charger on ebay, item number : 141000076411
(Had that recommended to me by spruce on this forum, and its been great)
Leisure battery i have is 85ah but from what i gather i'd get the highest ah you can (especially if you dont do alot of driving) as you'll get more out of it.
As regards to where to get it from, i'm not overly clued up to be honest. Mine was ebay again and its lasted around 15/16 months and still going strong.
Make is Marina and i hear Yuasa is a good make (ebay item number : 400543880209)