Hi Steveo,
Does either of you have insurance?
On the question who bears responsibility (or more responsibility) for the accident, this is a matter of he-says-she-says unless you have external evidence supporting your version of events. Therefore:
- Get a mechanic's opinion as to how the accident could have happened (e.g. at what speed was your car hit)
- Were there any witnesses who can support your version of events (that you were reversing first)?
- Are there any surveillance cameras around that could have recorded what happened?
- Obtain an insurer's report (if you have insurance)
- Was police called (and a police report produced)?
Basically, if they are claiming damages from you and you dispute that you were responsible (or fully responsible) for the accident, then they will have to take you to court (and prove that you should pay) for damage of property. From your facts, you sound like you have a good defence and set-off.
As for who was responsible, a driver reversing from a car spot needs to scan their environment and has a duty to ensure that it is safe to back out (i.e. environment free from cars, people, hazards). Having said that, you, as the driver who was reversing as well also have a duty to scan and stop your car in time if you see another car reversing out. There is a duty to respond to dangerous situations in time. The RACQ
has a good article on responsibility in different situations: if both cars reverse from opposite car parks and neither car was stationary at point of impact, both cars are responsible equally. You should figure out the total costs for both cars and agree to share the costs equally. The road rules are fairly similar across states in Australia, but perhaps contact RACT to confirm that this also applies in Tasmania. Further, this
handbook on Tasmanian Road Rules may also help.