Ok. Picked car up last night and problem sorted. It would appear that the catch failed completely.
The only way Victoria Audi could open the bonnet was to cut the grill off the car, then remove the catch. Glad i didn't have to see that.
They got new parts flown in from Germany and the car is now good as new apart from they've put my laserrrr umm, garage opener back in the wrong place in the grill, so will have to move that (would have been useful if they'd called me to check about it, numpties)
Overall;
Problem rectified under warranty. No quibbles.
Work done to my satisfaction, apart from putting the opener back in the wrong place.
Car wasn't valeted when i got it back. Not a huge issue, but the dealer i got my car from would have done this (car was pretty clean anyway)
Leather is dirty on the seat bolster which is annoying, but i'll sort that.
I had to call Victoria Audi on day 1 and day 2 to get progress reports. Fair enough, they called me on day 3 to say the car was ready, but progress reports would have been useful when they said they thought the car would only be in for the day.
They didn't pay the congestion charge for me on the morning i took it in. Fair enough i guess, but the only reason the car into the zone was becasue it needed WARRANTY work doing on it, but i guess you can't ahve it all.
Overall, 7.5/10 for Victoria Audi.