At the moment in the options, settings for toll usage is either a default allowed (ticked box) or not allowed (un-ticked box). Is it possible to change this so that it asks if you want to avoid toll roads for each journey in the same way that tomtom does?

No, however on the route summary screen there is an icon if you're routed through a toll charge or ferry etc, Tapping this area will jump to the route settings menu where you can change the settings.

It is the same in Primo 2.0.

Thanks for the info, will keep an eye out for it