Apparently there is an internet con which features cars selling at cheap prices. The seller claims that the car isn't with them but is expected to return from holidays/valeting/ servicing/ loan to a relative etc. Insists on payment, arranges delivery etc. All this can easily be solved by looking at the car, verifying all of the data in the advert, HPi checking and viewing the registration docs. It is fashionable for some dealers to "misprint" things, accidentally swap the descriptions of vehicles with other (coincidentally better) descriptions of other vehicles they are allegedly selling, Notice how may of then are at pains to tell you that a car has a leather covered steering wheel and or gearknob when they know that joe public word searches for" leather" when looking for leather seats.
Look at the car for real and ask to see all of the documentation is what I would do.Dont meet on motorway services, meet at their home or business address( depending whether it is trade or private sale.