difficult to answer, without you defining a syllabus, and how you define "professional".
and how you "certify" a student as having passed. (eg, extra training if you dont get it first time)
I am willing to invest in myself, if I can be shown things such as;
recommended account size (some may be willing to pay £5K, but if, in order to trade professionally, they need a bank of £50K minimum, for example, they may decide the £5K, while worthwhile, they may not be able to get their hands on the minimum bank size)
a good track of record of past students who are still trading successfully 3, 5, 10 years after being trained.
anything likely to yield a good return on £5K is worth trying.
EDIT: some may say £5K is too much, but think of it as: if it means you lose 5 fewer pips per losing trade, and make 5 pips more per winning trade, through superior knowledge, that can help improve anyones bank balance.
I've read too much on this site to be anything but suspicious of all training courses.
No.