As far as I know, any source that will total 13.6 vdc will charge a lead acid battery. ( a typical 12 volt lead acid battery when fully charged will equal 13.6 vdc). And you will need a current source that will deminish as you approach 13.6 vdc. I used a Radio Shack Battery Eliminator to charge a lead acid battery.. worked just fine. I don't know if Radio Shack is in the UK.. don't remember from my travels.

DS.