Skoda Octavia Mk 2 Indicator issue

Hi all, wonder if anyone has come across this problem. I've a 2008 Ocativa Combi (MK2), I'm having a problem with one of the front indicators - the left front. The light on the display keeps coming up saying that a bulb needs replacing and when you check, the light isn't working. However within a day or so (sometimes shorter) the error clears and the indicator works away fine. I've changed bulbs, checked all wiring and checked to make sure the bulb isn't working loose. Can't find anything amiss. I've had my mechanic check it out too with diagnostic tools and he can't find anything either. If anyone can shed any light (excuse the pun!) I'd appreciate it, or even point me in the right direction. Only thing I can think of is contact my local skoda dealer (where i bought the car new) and see if they have seen the problem before. Or would they have better diagnostic equipment? Any comments appreciated. I've my NCT coming up in a month so need to get is sorted before then.