Hi Ken
Welcome to the forum and welcome to the never dull world of Car Dealing.
Online buying is a great idea to help widen the appeal of stock, but if you are new to the game then there is nothing better than actually eyeballing the stock. As you start to get a better feel for the types of vendor and what works then buying online is less of a risk. It does sound like you have been a tad unlucky and in the case of the BCA experience, you may find you have some recourse if there was a major mechanical defect, however it depends how bought and how significant the problem was.
I would speak to BCA in the first instance, however until you are really comfortable, you simply can't beat kicking the tyres
Andy