NCB diminishes by a certain percentage, it is not lost entirely unless you had only a few years.
For example maximum NCB may be 80%, 1 claim means it falls to 45%, 2 claim means it falls to 25%. That not withstanding, a claim has a significant impact (=A3350 Yr 1, =A3250 Yr 2, =A3150 Yr 3 =3D =A3750).
Since it can cost =A330-70 to protect a NCB which over 5-10yrs is better off stuffed in any loony fund boosted to 10/month.
Remember real inflation is about 5% as far as the banks are concerned, or soon will be, so =A3200/yr premiums may get harder to get. Insurance also tends to go up past 15yrs on a vehicle and TPFT is hilarious for hiking premiums. Never renew close to the renewal date, they put the figure up 10-20% because they know you are getting short on time.
I suspect insurers may have been stung by a lot of fraud in the recession, re trade & domestic car policies.