Yes - cyclone (blue part) COMPLETELY disassembled. Lid, fins..everything. Water flused through the lot. No evidence of any dust/debris in any part of the cyclone assembly after cleaning. All cones at the top completely clear of everything. Totally clean. The whole lot was put back together. And the FDC is gripping the bin lid tightly. There no holes or gaps in the FDC or the seal it's making with the bin lid. Integrity of the seal looks good. Suction after cleaning (and pre-motor cleaning) is excellent (pulls the carpet up slightly as you push it around) and the bin fills up nicely. And then the suction tends to reduce as the pre-motor filter clogs up. By the time the bin is completely full, filter is clogged and suction is greatly reduced.
Maybe I should just get a new FDC after all