Hi
Just taken another look for you.
The fitting at the bottom of the regulator (bottom of pickie) is an isolation valve which feeds the items in your van like cooker etc. The green bit at the other end of the regulator looks like the handle on a two way valve (change over valve) in to which the two high pressure hoses fit (NOT ordinary flexible hose as that would expand and burst under pressure). Thus depending on which way the green handle is turned, depends on which bottle in on line (suppling gas).
Just had a quick search for a similar setup, but could only find an automatic c/o set, and that was about £70 plus £8 p&p. so a manual set will be less.
You know wher I am for further questions.