A long time has passed since this subject was first raised but I have some history with this problem which may be of interest.
The camchain on my 170,000 mile 1998 A4 B5 1.8 became very noisy, so my very friendly Audi Mechanic had a look and found that the plastic tensioner pressure pads had broken up leaving the chain running on the metal.
A new one was around £230 from German and Swedish who do pattern parts (or sometimes Audi ones). This was too expensive for me, so he fitted another one from a scrapped car for £100 and this was fine for 5,000 miles and then became noisy again.
He fitted another OEM one from a scrap engine which lasted 6 months, but had in stock a new Audi one which he had bought years before with a job lot of spares. This did not have the VVT electrical drive but looked as if it would fit - so I told him I would take the gamble and to fit it for around £100 for the whole job including parts.
The car now runs very well, has done 8000 miles with no noticeable loss of performance and the fuel consumption is better by around 10% which was a surprise.

The only remaining worry is a short 1 or 2 seconds rattle in the morning sometimes as the oil pressurises the tensioner, but otherwise the motor is mechanically very quiet when running.
A new camchain, which takes longer to fit than the tensioner assembly, might cure the rattle but for the time being I will live with the rattle unless it becomes much worse.
I have read that there is an oil retention valve to stop oil running back into the sump when the car is left standing and that if this is jammed open the chain will rattle until pressurised oil reaches the chain tensioner. This may be situated behind the oil filter mounting casting. I can not however find any reference to it for a non Turbo 1.8 engine in my A4 Haynes repair manual, but suspect it would be a big job to find out if one is fitted and if so is it jammed open.

I am a retired professional Engineer and at one time could have easily done all the work myself but at 80 years am beginning to find it physically hard these days.
My Audi mechanic however is a one man band and for instance has just provided me with an MOT certificate for the car having changed both drive shaft gaiters, all 4 new brake discs and pads, a front suspension ball joint, and replaced a front brake calliper with a second hand one - all for £350 - it does not seem to be worth getting my hands dirty !!!