The post you are reporting:
Unfortunately, or possibly fortunately, there is no site which plots more than a tiny fraction of the worlds shipping movements. The various AIS sites just give a snapshot of a patchwork of localised areas where amateurs have set up their own AIS receivers and are feeding the results onto the web. AIS works on VHF so those hobbyists will only be picking up ships within a radius of maybe thirty or forty miles, depending on how high their aerial is above sea level. The sum result is therefore just a patchy mosaic of small areas on the fringes of inhabited coastlines. The whole of the rest of the world's oceans and coastlines are therefore not covered so we are only talking about a very small percentage of cover.
All merchant ships were required to fit AIS a few years ago. It enables them to identify vessels in their vicinity and obtain various static and dynamic parameters. I was involved in the initial experiments conducted in the nineties when seventeen local Dover Strait vessels trialled software mods to their VHF DSC gear in an early evocation of what was to evolve into dedicated AIS equipment. Although it is useful to us, the real reason for requiring it to be fitted is so that shore stations can keep an eye on what is in their area. The Americans are pushing for a long range version so that the whole surface of the world is covered.
The gear now fitted is very compact and only constitutes a small LCD display on the Bridge with an associated shoebox sized transponder; and a VHF aerial and GPS aerial, frequently combined, on the monkey island. The dedicated GPS is just used to keep all ships AIS in the area synchronized to a common time as the data is exchanged on time division multiplex, the actual ships position is derived from its DGPS equipment. The AIS is linked to the ECDIS (Electronic Chart Display) to display the received ships as an overlay on the chart.
A Dutch company, later taken over by Lloyds/Fairplay, started AISLive which displayed AIS info on the web. This was free to begin with and mushroomed. However, the IMO took the view that this was a gift to terrorists and pirates and required that the free service was delayed by a variable time around an hour. The free service was later withdrawn and real time AISLive is now only available to vetted subscribers in the professional maritime world. Since then, all the amateur AIS sites have started up. What the IMO thinks of this is open to question. Any self-respecting terrorist or pirate would invest in their own AIS equipment anyway, not expensive.
If your friend has given you an expected itinerary, then it may be worth Googling for the port websites of the ports they will call at on the way home in order to take bunkers, also the Suez Canal site. You will be able to get the times of the vessel's arrival and departure.
The sailwx.info site you mention is most unlikely to show the Norman Arrow. The 'wx' is our abbreviation for weather. It is a site showing received weather observations from voluntary meteorological observing ships. These only constitute a tiny fraction of the worlds shipping. Ferries do not take weather observations as the areas they operate in are completely covered by land stations, and the navigators are too busy to take the observations anyway. It is extremely unlikely that the Norman Arrow will register as a voluntary observing ship just for a single passage from Aussie to the UK, unless your friend has advised you otherwise. Normally a ships master will volunteer his ship, or have his arm twisted to do so, and that ship remains a voluntary observing ship for the remainder of its life.