T756 pages, We are looking at 2 different documents then.
Where did you get it from?
The code for transport?, available from here:
NTC - National Transport Comission
Does not contain any Regulations, it is the technical reference.
The regulations for Vic is what I am looking at, available here:
DANGEROUS GOODS (TRANSPORT BY ROAD OR RAIL) REGULATIONS 2008
The copy I had on my laptop was out of date 
but the rule I referenced is correct:
Rule: 26 Special provisions for tools of trade and dangerous goods for private use
For those not in the industry LPG is classed as Division 2.1
(1) This regulation applies to a load (an applicable load) if?
(a) the load includes?
(i) an aggregate quantity of dangerous goods of less than 500 that does not include any dangerous goods of Division 2.1 (that are not aerosols) or Division 2.3 or Packing Group I; or
(ii) an aggregate quantity of dangerous goods of less than 250 that does include dangerous goods of Division 2.1 (that are not aerosols) or Division 2.3 or Packing Group I, provided that dangerous goods of Division 2.3 and Packing Group 1 together constitute less than 100 of that aggregate quantity; and
(b) the goods are not being transported in the course of a business of transporting goods but are being transported?
(i) by a person who intends to use them; or
So the scenario of having it inside a 4x4 for the purpose of touring is acceptable
(ii) so that they can be used for a commercial purpose.
(2) A person transporting an applicable load is exempt from all obligations imposed by these Regulations other than those imposed by this regulation.
(3) A person must not transport an applicable load unless each package in the load?
(a) complies with the packaging requirements appropriate to the quantity of dangerous goods, as specified in Part 4 of these Regulations; and
(b) is appropriately marked (defined in regulation 5); and
(c) is loaded, secured, segregated, unloaded and otherwise transported in such a way as to ensure that?
(i) its packaging remains fit for its purpose; and
(ii) the risk to any person, property or the environment is eliminated, or if it is not possible to eliminate the risk, is minimised to the maximum extent that is practicable.
i.e. window open a fraction or other ventilation, keep out of direct sunlight, cylinder upright etc
(4) Omitted, irrelevant for this discussion
(5) If an applicable load contains an aggregate quantity of dangerous goods of Division 2.1, Division 2.3 or Packing Group I of more than 50, a person must not transport the load?
(a) in the passenger compartment of a vehicle; or
(b) in any other enclosed space in the vehicle.
So as long as you keep the aggregate quantity under that 50L threshold you may transport it in the passenger compartment
The Elgas website gives the fill capacity of a 9kg gas bottle as 16.6L
Bookmarks