Has anyone taken out the factory reverse sensors and found a replacement kit that

a. fit the existing holes in the bumper
b. don't break every 6 months.

I'm fed up with mine, I've had the bumper off 4 times now to replace sensors, which isn't a quick job (involves 23 screws and nuts).

I'm not that bothered about making them flush fitting - I had a £20 set from ebay on my last car which worked better than the Audi ones..