This is what I was looking for Russell, better late than never I guess
Licence categories
There are a range of categories of licences in Victoria. These also include marine and tow truck licences. Taxi licences are the responsibility of the Victorian Taxi Directorate (VTD).
Below are the categories of licences and what you need to do to apply them.
Licence categories
Description and Eligibility
Car
You can drive a vehicle that does not exceed 4.5 tonnes Gross Vehicle Mass (GVM) and can seat up to 12 adults including the driver. This does not include motor cycles and motor trikes. You may tow a single trailer (other than a semi trailer) up to 9 tonne GVM or to the manufactures specifications (whichever is less).
Can drive as soon as you get a car licence.
Motor Cycle (R)
You can drive a two or three wheeled vehicle that includes a sidecar, forecar or trailer and includes a motor trike. Can drive a motorcycle that is permitted under the Learner Approved Motorcycle Scheme as soon as you get a motorcycle licence.
Marine licence
A marine licence allows you to operate a motorised boat in Victorian waters. You can also have your marine licence endorsed to operate personal watercraft.
You must be at least 12 years of age to apply for a restricted marine licence.
Tractor
See Driving a tractor for more information.
Light Rigid (LR)
You may drive any rigid vehicle, including bus and truck, greater than 4.5 tonnes GVM but equal to or less than 8 tonnes GVM or a vehicle that seats more than 12 adults including the driver that has a GVM not greater than 8 tonnes GVM. You may tow a single trailer (other than a semi trailer) up to 9 tonne GVM or to the manufactures specifications (whichever is less).
To apply for this category you must have held an Australian car driver licence for at least 12 months.
Medium Rigid (MR)
You may drive any two axle rigid vehicle, including bus and truck, greater than 8 tonnes GVM. You may tow a single trailer (other than a semi trailer) up to 9 tonne GVM or to the manufactures specifications (whichever is less).
To apply for this category you must have held an Australian car driver licence for at least 12 months.
Heavy Rigid (HR)
You may drive any rigid vehicle with three or more axles, including bus or truck, greater than 8 tonnes GVM. You may tow a single trailer (other than a semi trailer) up to 9 tonne GVM or to the manufacturer's specifications (whichever is less).
To apply for this category you must have held an Australian car driver licence for at least 24 months.
Heavy Combination (HC)
You may drive a prime mover or single semi trailer exceeding 9 tonne, or rigid vehicle plus trailer greater than 9 tonnes GVM. A Mass and Dimension permit may also be required. Check with VicRoads by calling 13 11 71.
To apply for this category you must have held an Australian car driver licence for at least 24 months, including Medium Rigid or Heavy Rigid licence for at least 12 months.
Multi Combination (MC)
You may drive a heavy combination vehicle with one or more additional trailers.
To apply for this category you must have held a Heavy Combination, Heavy Rigid or a combination of Heavy Rigid and a Heavy Combination vehicle licence for at least 12 months, plus the completion of an approved course.
NOTE: Light Rigid, Medium Rigid and Heavy Rigid licence holders may tow a single trailer (other than a semi - trailer) that has a GVM not greater than 9 tonnes.