I don't remember the link P1 but if you're anywhere near me the guy who did mine will do an autocharger and analog flow regulator for £150 fully fitted all in. And he'll come to you if your near...
I think it was this one : http://www.ebay.co.uk/itm/161145396601?redirect=mobile that spruce from this forum recommended that i used (although mine had an orange surround around the relay)
I'll text him now...