Ok so I am not expert but since I changed my cam chain on my Eddie I am paranoid about noises. Changing the chain solved my issue but it didn't sound like your noise. Things to check.. N80 evap purge valve does make a ticking a little like that, all the GTi's do but some can be louder than others and its normal. Its at the front of the engine on the right as you look at the engine. It doesn't sound like injectors either as they are more a background level of ticking.
Hold the valve or use a screwdriver to touch the body and see if the timing is the same as the noise.
Check this link here to see where it is
http://www.golfmkv.com/forums/showthread.php?t=119267Something else to check is the fuel pump but I have a feeling if its doing that then you could have a problem as they don't tick! Finally can you get anyone to check for any DTC's using VCDS to verify no errors? If there aren't any I would suggest you could just live with it?
Rip.
