looking for some advice please, on the ex21 there is a teardrop shaped tension lever above the blade holder, mine keeps flipping over, releasing the tension, I used a rubber band to hold it in place and assuming it was worn I ordered a new one. now this is where I need help...How on earth do you remove the old one, it looks to have a metal tube about 1.5cm long running through the casing, through the tensioning lever and into the casing again. because its flush with the casing there is nothing to grip to pull it out, I tried tapping it through with a metal bar of similar diameter, it did not budge and not wanting to cause any damage I have come to the village for help. The only reference to it I found on the internet said it was easy to change, but not how to do it, can anyone tell me how...'Please'...