Thanks John, any more tips on battery maintenance then ???

I've gone with these batteries after a bit of research...

http://www.elecsolbatteries.com/products/Leisure-Batteries/Elecsol-100.html

As the site is unmanned most of the time there isn't anyone there to check on a daily basis and I visit every couple of months (on average), so how regular do I need to be checking things ???

Cheers

Cris