Can some one advise me on the wheel nut size on a?

Go to your local parts store and get on of those Cross up 4 size wheel wrenches, get a metric one, one size should fit. Torque isn't critical, I go second grunt tight on mine, 70 ft/lbs should do you. That's about 10N.m. For the correct spec, call your local Mitsu dealer, and ask.