Flight connection time in CDG - returning to origin
 

I have an odd trip, because my travel plans changed I am flying to Paris via LHR from YVR, but now I want to stay in London. I called BA to change my ticket but it has been tough getting through to them. My travel agent says its $450 to make the change I need through them so I figured it would be easier just to fly to Paris, and then fly back to London as it only costs $80.

So my question is how long I require for the connection to fly back to London. I assume that if I take the same flight back which is 30 mins later I should be OK?

Thanks in advance.

No way!
 

If you do not have checked bags, then just walk off at LHR.

If you do have checked bags, you will need to collect and re-check them, so forget the possibility of a 30 minute turn. Also, in addition to the possibility of a delayed arrival, you may need to change terminals. I'd allow nothing less than two hours.

is it a one way or return flight?

If you booked one way and can fly with hand luggage only, I'd just get off in London - if return, I wouldn't want to risk them cancelling the rest of the ticket due to a missed sector.
(I have once successfully argued that the system must have screwed up when they cancelled my return flight from HKG based on missing a leg of the outbound journey - but I wouldn't want to rely on it. I had flexibility and knew there was rewards space to book in should they not let me on a plane)