After a bit of thought and research (
http://www.golfmk6.com/forums/showthread.php?t=55992) I decided to swap the tensioner on my 09 GTi myself. After all, what could possibly go wrong.
I'm lucky in that I have quite a good selection of toolsand a large trolley jack, but additionally I bought a genuine VW crank pulley holding tool at £32 and a 12mm spline tool, which is different to a Torx.
Pretty straightforward to carry out as long as you take your time. I have some pix if anyones interested. It took me about 4 hours to do, but having done it once, next time would be 3 I reckon. I was going to do the chain as well, but they are on back order for 2 weeks, so I didn't bother.
The result? With bated breath I turned the key. Engine was perfect, no rattles and even on subsequent hot starts is a lot quieter. Cost of parts was £120 from TPS. Bit of mider, but I saved myself £100's.
Very happy with myself!