Best product to remove dull, oxidised car paint?

3M rubbing compound. I haven't tried the other products you listed but thats because 3M works so well for me. Why fix what ain't broke?

Please do yourself a favor next time and go down to a paint store that sells automotive paints and ask a few questions or go to a body shop and get an estimate of what it would have cost to polish this out. First of all the paint from the fence while unsightly was almost dry when it hit your car. you could have used a cleaner wax from almost any company from turtle wax paste cleaner wax (paste wax lasts a lot longer than a liquid wax) and the overspray would have come right off. When you used the petrol you stripped all the wax off the cars finnish too. you needed to go right baxk over what you stripped off with a good car wax to put the shine back in your paint. At this point a good paste wax car wax should put the finnish back on the car you stripped off with the petrol but do it sooner not later or bettere yet get a professional hand wax from a local automotive detailer and send the bill to the person painting the fence.

I would suggest a rubbing compound of no specified type. the best way to obtain a "new car" finish would be to have it professionally buffed tho