Cockney rhyming slang (berk) (Was James the Berk)

[justcarol67]

No: HPFGUIDX 106116

. . . .Sylvia (who heartily endorses the motion that James is a berk,
but hopes our American cousins realize that this is Cockney rhyming slang)

Carol:
Hi, Sylvia! I tried to respond to your July 5(?) Mark Evans post off
list (R.I.P., Mark the Muggleborn! I miss you!) but my e-mail bounced
back--I hope the List Elves will forgive me for mentioning it here.

BTW, my request for the James defenders to step forward was not
intended as a challenge to a figurative duel. I only wanted to hear
what they had to say, preferably in a straightforward, canon-supported
sort of way. So I hope I'll be forgiven for declining Valky's
invitation to sharpen my Snape fangs. I don't think or react in those
terms, sorry, Valky! I also think the main reason for liking James
should be that he outgrew his "arrogant little berk" phase.
Fifteen-year-olds are children, and fortunately for the WW, he didn't
remain a child. But I'm not going to argue with anyone who's convinced
otherwise. I'll just agree to disagree.

Almost forgot the point of my post, which was to ask you for a
clarification of your Cockney rhyming slang remark. (I'm one of your
"American cousins," as I'm sure you know, and I've never quite gotten
the concept.) Berk = jerk? And wasn't it Sirius himself who first
applied the term to James and himself, so if *he* admits it, maybe
it's JKR's view, too?

Also are there any other examples of Cockney rhyming slang in the book
that we should know about? And on a somewhat related note, Steve (I
think) mentioned Ron calling Harry "mate" in  OoP--the first time he
does so in the American editions. Does he do it earlier in the British
editions? (It grated on me at first; it seemed as if he was trying to
sound like the twins.)

Carol, still trying to get caught up but having to skip a lot of posts
to do it!