Course you're not qualified to call yourself a plumber after 2 weeks. Silly question really. Or 2 months, or two years.
In the US you have journeymen and master tradesmen, I don't know if they have a grey are in between, or if they wake up one day and they're no longer a journeyman but a master!?
Anyway in this business you never stop learning, the minute you think you know it all, Karma will come and bite you on the ars*.
But after TWO poxy weeks, I wouldn't let you change the water on my kids goldfish, let alone come swinging in my home with a wrench and a blow torch. Yeeehaaa!
Abridged: Yes - NVQ Lvl 2 - plus various gas qualifications, solar, ground & air source, unvented, few other random quals too. Served my aprentice time working for time served plumber/heating engineer (my darling father!)