as i understand it, "trading" as a "trader" and "trading" as a "non trader" are seen as 2 different things

"traders" are people that are seen to be something to do with the car industry mainly, but i think some of the pf builders have also fallen foul of the "trader" rules

if you are simply selling your own car but are still acknowledged as a "trader" then you have to shell out (i think) £600 a year to have the trader tag stuck under your name and then you can flog as much stuff as you like

hope that helps, but i've probably confused you even more