1990 Peugeot 206 car is rattling when starting till i press clutch in and out and makes odd noise

Sounds like clutch ass. fault , possibly bearing but would mean dismantling to examine .

if it is the clutch bearing,, is it dangerous to drive?? the garage i always use is shut till friday,, its not doing it all the time?

Hard to say for definite without hearing noise , if it clutch ass . just an educated guess .If it is , you should be o.k using car especially if it comes and goes . Could also check engine oil level just to eliminate another possible cause .Hope this helps .

the 206 suffers from the gearbox input shaft tube braking up but still means gearbox removal to check

That happened with me too, it was the clutch on its way out. I suspect that is what's wrong!

same problem with one i had many years ago have clutch replaced dont buy cheap either as some clutch kits the bearing colapses just be aware best clutch kits ive used so far is luk clutch kits