406 Cambelt tensioner

Hi I have a 98 406 V6 it's been in to have it's cambelt changed, the trouble is it's been in for over a month already and still waiting for the tensioner to be imported from France. I'm spitting feathers, heard today from the garage that it'll be at least 15th Sept before the part is delivered to Coventry and then I suppose at least 2-3 days before I get my car back. All the other parts have arrived and the car is all sorry looking with it's engine dropped etc waiting. The car is at a reputable garage (not main dealer as they quoted £1,100+) that has been servicing the car foir years, not had any problems with them before and they're very apologetic but stuck as am I. I don't know what to do. Has anyone had similar problems getting parts? One option is to put it all back together with new belt, rollers etc but with the existing tensioner, any advice as to if this is sensible? The garage owner is in two minds, aside from the cost (of replacing the tensioner when it does eventually become available) would the old part be put under extra stress from the new parts? Would driving it gently be enough to ensure it didn't break completely? I'm really stuck, any advice would be a great help. I'm missing my car badly!! I'm currently driving a Corsa 1.2 which the garage have loaned me but it's just not the same (very econimical though lol) Please help Thx Chris