Hi there!
Accent problem? Bah! G'day mate, get a fellow cockney to do it for you.
I have just completed a *huuuuge* transcription project for another user here (48m, 90m, 140m tapes) and he will hopefully soon reiterate how happy he was with my work on a formal site review. Edit - this is now available on my review history.
My bid is a rule of thumb, three hours work per one hour's talk bid - 45 minutes at $15 / hour. If the job is faster, I am happy to discount - if it takes longer, that's the most you pay.