No suction in hose on my dyson DC01?

I love my DCO1 and don't want to bin it . It sucks well on the floor but there is no suction at all through the hose. I have taken it apart as per the instructions and checked every conceivable place for a blockage but cannot find anything wrong. Everything is clear. It is however blowing a lot of air out from beneath the premotor filter area from the vertical struts area when in the upright position but sucks well into the bin.

Can anybody help. Dyson will charge £63 for a callout to check.