Gas regulator on swan campervan.

Hello

We bought a jayco swan a little while ago (2005 model). I havent been able to get the gas going in it, and today I realised gas wasnt getting through the regulator. It has a regulator which I havent seen before, 2 seperate parts to it.
Anyway, my neighbor gave me a new regulator to use on it, but its just your standard bbq regulator you use on the 9kg bottles. So just wondering if anyone knows if I need to replace the fancy regulator or I can just use the common type?
The other question regarding regulators is about a little portable bbq I bought from the hardware shop. It says you have to use 3kg max bottles on it and I was wonderign if I can just put a regulator on a 9kg bottle and use that on it?
I know this isnt a bbq forum but with all the knowlegeable campers on here I know you guys will know the answer.
thanks

regards

Justin