The chassis number will be written / typed in vehicle's original owner's manual.
If the vehicle was purchased from a licenced dealer, the sale documents should specify the VIN.
If the vehicle is currently registered, a free, online rego check with the applicable State authority will show the vehicle's VIN.
The chassis number is actually stamped into the front section of either the left or right chassis rail. If someone crawls underneath the front of the vehicle with a torch and a rag (for wiping the surface of the chassis rail/s), they should be able to find it.
The vehicle's original chassis number - along the lines of HB3100XXXXX - does not meet the current 17 digit requirement of a VIN so it's probably been added to.
Thankyou very much Mein for your prompt reply, I was able to locate the number immediately with you detailed instructions, it's on the passenger side on the chassis in front of the shock absorber.
Kind Regards Wizard 1.