Currently it's sat on ET30 wheels.

The thing is I would want to try the car out on the right set of wheels. E.G. buy the right offset (will need around ET24 to add another half inch of width) then I'm unsure what width tyres I'd use. Once I got the wheels I'd want to drive it for a few hours to get a feel of how it drives/handles/grips and if the arches are at risk of being ripped off when cornering! I'm either going for a 17x7 or 17x7.5 wide wheel around ET22-ET24 ish.

I'll be at National Day for definite but I'm not sure about other shows yet.

The MH600 Datapost wheels are about ET12 and ET8! Thats why it's never been driven on the MH's.