Hello,
Maybe im too late, but some experience from me.
I was driving A2 for few months without CCU. What doesn't work: el. windows, interior lights, central lock, boot lock and fuel cap. Also, no parking brake lamp
How to overcome these problems. If your CCU is still a little alive, connect it, use central lock to lock rear doors. Disconnecting CCU will leave rear doors locked and both front will be lockable by key.
If you want to refuel , open your boot by using emergency "hatch" , then remove right side plastic cover for lamp inside boot, and push down the "cylinder" to open fuel cap.
I sent my unit for repair to Lau month ago, he received it in 3 days, sent back another day. Tho, received it after 20 days, but it's because Lau sent it on Christmas, so long delay from German post
Hope it helps.