I have been dealing with these VAG door locks for years now and the revving/battery support trick sounds like great idea which i will definitely try next time i get one in although as everyone knows sometimes the customer has simply left it too late and we have to do things the hard way!
A trick i have used for sometime now when it refuses to open is to simply either carefully remove or drill through the outer door lock barrel cover cap and blank (doesn't work on the drivers door unfortunately due to it having a lock barrel fitted) and with a couple of well aimed punches with a long heel bar in the right place, split the lock apart and this releases the deadlock allowing you to open the door and replace as normal, saving hassle and expensive of trying to access from the inside by removing trim and regulator.
As a general rule if the lock barrel cover cap is painted i tape around it and carefully remove (simply clipped on) or if its just bare plastic sacrifice it as they are only a couple of quid from TPS and usually in stock.
Hope this helps when all else fails!
Cheers
James
Copyright © uk autotalk