Welcome Peter.
To some extent, I think you have answered your own question, by saying that the car hasn’t given you any trouble over its 187K miles. This equates to not having had to spend too much on it to date, but now it’s catch up time, and it needs some funds spent on it wisely (in caps).
So if you scrap it, what are you going to do for on going transport?
Of it were mine, I would be search out a trusted localish Audi independent and seeking advice there.
Perhaps you can come back to us with an answer to the question.
Kind regards,
Gareth.