Hi Richard,
I only flightsim on laptops as I live in a remote area and rely completely on solar. I would recommend you check out a Perth company called Metabox. They have been doing really well in reviews and their laptops punch well above their weight. The last review I have was for the Metabox Prime PE650RE (GTX970M). It had the second highest fps on 3 different games, tested with 7 equivalent laptops. I also notice that the higher end Gigabyte laptops consistently do well in comparison with other laptops. The last review I have was for the Gigabyte P57Wv5 (also a GTX970M). Personally, I have a Venom 15S which I have been very happy with. It is by no means a high end machine, but I have no trouble at all running FSX with the ORBX recommended settings, and some REX weather.
Hope this helps...