I'm just wondering if anyone has used puncture repair kits like the tire liquid sold at supercheap auto
http://www.supercheapauto.com.au/online-store/products/Liquid-Patch-Puncture-Sealant-1-L.aspx?pid=153605&menuFrom=100210#Description

if so do they last long/permanently? It says long lasting but I have 2 flat tyres in the back that I need to put back on the magna.

Take the tyres to the experts, It's not worth your life. Most of that stuff doesn't work and will void your tyres warranty

They are more of a 'get you home' repair usually so you can get to a tyre shop.

Well to be honest the tyres have been off the car for about 2 years but there is still a decent level of tread, would that still be okay?

If the puncture is on the tread and not on the sidewall or the edge of the tread, it's usually fixable by a tyre from for a negligible fee.

How old are the tyres? If they're more than a couple of years old and they're a smaller size, it may make more sense just to buy new ones.

Well to be honest the tyres have been off the car for about 2 years but there is still a decent level of tread, would that still be okay?

Then chuck them, rubber perishes, would bet they are 4 or 5 years old, I see many blow outs from over old tyres

I guess it's better safe than sorry, I do have 235r17's from an xr6 BA model on at the moment but they are quite rough, on the downside, 15's just look so out of place but are much smoother.

The aerosol cans are to get you home only (read the fine print). Also, I once had to fix a tyre fitted with a tube that had been fixed with the aerosol can and the whole tube was bonded to the inside of the tyre.

It's only about 25 bucks to get the job done properly at a tyre place. But I'd be going new rubber rather than running old ones.