the company has given us approval in FCOM to do it prior
Would be interesting to see if there was a no objection from the manufacturer for that. Last time an Aussie airline mucked around with the Airbus checklists without consent, they got within ~30 feet of the ground at YMML in fog in a stuffed up go around.
How "prior" do you do it? At the gate? Trundling down the taxiway? With the Before Takeoff C/L above the line?
The whole point of the takeoff runway confirm is to check you are lining/have lined up on the correct runway, not a taxiway, and pointing in the right direction. Not much point doing that before you're at the holding point and about to initiate the turn to line up.
You might think it can never happen to you, but the reason Airbus brought the check in was because people kept doing it.