Streeka indicator problem

The rear offside indicator of my Streetka works OK when the car is stationary (most of the time) but when I'm moving it clicks double time and gives a quiet but audible alarm tone. I've changed the bulb but no difference. When I can get it to NOT work when stationary (rarely as I've said) the indicator bulb can be seen to glow VERY VERY faintly. Where do I start ?
Any advice gladly received - Thanks