Replaced the alarm horn this morning, and it now works and fault has gone. No obvious signs of leakage externally. The one I replaced it with from A8Parts :) has the same part number, so I guess will go the same way eventually.

Try taking the old one apart to investigate?

If you do a search I'm sure someone on here did once and sucessfully repaired theirs but it depends upon how far gone it is. +++. Edit: found the link HERE it was Daz.G

How you getting on with your handles and heaters?

I got the same issues.

I suspect many has as they seem very commoin.

I've not looked at either yet, the heaters i'll leave for the time being because once we get decent weather they won't be needed anyway. Handles I'll see how they go, but as long as I can get in/out and lock the car with it remaining locked all is good.

That's my thinking for now.

I will have to get them all fixed, I do like a nice clean scan.

I've never seen a D3 run a completely clear scan, they like to log erroneous fault codes at the drop of a hat. For example my sunroof works perfectly, but it sometimes pops a fault into the roof electronics for no reason at all. Just seems to be the way of the D3, the sheer number of electronic systems leading to phantom faults.

its always recommended with the D3 to clear all the fault codes and then go for a drive, then scan again and see whats cropped up and assume that these are most likely current issues.

I'm noticing that.

Always do a pre and post drive scans.

Dealing with the Touareg for errors seems to be the same.
We spent weeks chasing faults and all turned out to be a low battery.