Steering clunk after fitting new indicator switch

hello, hope for a little help...yesterday a mechanic replaced the indicator stork (and mounting assembly) behind the steering wheel. It took only 10mins, and all seemed fine. After 5minutes driving I now find that there is a defined click (or clunk) every time the wheel turns and re-passes centre. It's louder than the indicator cancel click (cancel works fine), but is certainly something to do with the blue collar - I can see it go ' 'clunk' but no idea why! When going to full lock (three rotations) it clunks three times. Is it possible it's just the wrong way around or something? The metal part behind the wheel that inserts into the blue collar seems to be fine and doesn't slip. Hope to fix it today, as up in mountains and can't pop into garage. Many thanks in advance for any advice. Andy.
2005 defender 110 TD5 (left hand drive) standard two spoke steering wheel.