No, Dojj normally waffles far more than that!
Kermitt, my cossy filter didn't fit either, i bought it from puss who had modified it to fit by cutting slots along the trumpet, much like many exhausts have on the slip joint, the trumpet can be closed up very slightly and the hose clamp get a good grip on it.
You can also try heating your silicone hose in boiling water, this softens the hose enough to stretch it on.
Good luck
Rob,