Desperately need some help!

ah that's a bummer, shame no one has replied.
How have you got on?

Personally in the same situation
(I am no car engineer so please do not take this is advice, this is only what I would do..)
smash the window to gain entry, disconnect the battery in the boot (might have to climb through the rear and lift up the carpet) to shut up the alarm, then from there get the lock smith out again, remove the door card and allow him to fix whatever rod has snapped..

reconnect the battery, try to lock and unlock via the manual key in the driver door.

Common fault on that model that the connecting rod for the locking mechanism for the outside door handle comes off of the mech. In that situation you can still open the door using the inside door handle (but not If the car’s locked due to the deadlocks that prevent this).

First they need to get the car unlocked and then they can open the door from the inside. They should know this. I’d they smash the window they can reach the OBD port, plug in their computer and programme a new key. Though it would be unusual that both keys are knackered. More likely that there’s something wrong with your central convenience module (in the boot)

In any case it would be much cheaper to smash the window, snap off the bonnet release handle (you can move it with the door shut) and then pull the cable with pliers to release the bonnet, than it would to smash the grill and remove the bumper.

There’s not enough info from the dealer here on the fob situation. What does “keeps losing it” mean exactly? Has their mastertech gotten involved? Have they spoken to Audi tech support in Germany? The dealers aren’t as clued up as you think. I had the rear LED kit retrofitted to my 2008 A5 by Glasgow Audi (an official Audi package with its own part number) and they struggled to code it. Dealer service manager was arguing with me on the phone but hadn’t even spoken to the mastertech. An hour later I got a call to say the job was done. Mastertech had told them what to do.

I would be tempted to speak to an indie specialist, explain the the situation and ask if they can sort it. The dealer may we’ll be out of their depth to be honest.

This may also help: https://www.audi-sport.net/xf/threads/central-convenience-module-and-remote-locking-problems.241328/