The 650i has good reviews in What Camcorder and Camcorder User but is not showing in many stores. Would it be safe to assume the 750 is the replacement?

I like the Sony TRV60 but am not sure I'll get on with On Screen Menu, bottom loading and on board charging. I can get one for about £660 from Empire but as video making is far from being a hobby it will have to have few features I dislike for that amount of money.

The 700 series does indeed replace the 600 series. Whether Canon has managed to solve the noise problem with the 700 series that plagued the 600's remains to be seen.
I think it is bordering on criminal how no mention was made of the motor noise in the reviews.

Not to mention rather duff picture quality.

I didn't think the picture quality in normal light on the Canon was bad. It was pretty awful in low and artificial light though. The 700's haven't totally eradicated the noise problem, but it is better than the 600's.
Just got a Sony HC40. Big smile.. BIG SMILE