Thanks for the input guys, As i said the lights performance is excellent. i just cant believe i've had two lights go in the same place.
this is the second light. the first broke both sides and had more material missing.
I've one of these 610s too, but my problem with it was the charger going (about a fortnight ago). I contacted Wiggle who said return everything back to them, but I can't find the receipt/warranty etc.
I'm just getting a local electric shop to rebuild the charger for me, but I was less than impressed.
Haven't had any problems with the rails etc as detailed above tho.