]one of the lines I´ve been unsure of to miss Bingley:

"I think I have heard you say, that their uncle is an attorney in Meryton"

]I thought it was mr Bingley or mr Darcy that said this

My thoughts as I read this part were like your own. I thought it was Mr. Darcy who spoke the line in question (Bingley doesn't seems as likely a candidate due to his next line where he tell the group he doesn't care what connections the Bennet girls have); Miss Bingley would probably have found out this information when her sister did, so would have no reason to ask. This is just conjecture though. As for the text, I've been reading it over... it doesn't really seem to give a clue as far as I see. Anyone else?