I must comment on Rays posting,
Regulators are sealed by the manufacturer, as opening them will compromise the proper and safe operation of the device.
There are no user serviceable parts inside. this is definitely not a DIY job
Once opened a regulator needs to be tested for gas tightness, and lock off, then it needs to be adjusted for the correct output pressure with the specified flow and sealed.
It is highly unlikely that unless you are an LPG engineer you will not have the test equipment and knowledge of how to use use it to satiisfy the Gas Safety regulations.
The regulator is the only thing that stops bottle high pressure gas reaching the appliances connected to the installation, and as such it is a primary safety device.
It is irresponsible to suggest that a regulator is serviceable by an end user with no gas competency.