Got round to doing the greasing as beautifully described by "xrayrider" in page 3 (thanks for the pics). Drove her up onto an upturned Guinness crate in lieu of a proper ramp! No matter : the access was great.
Used at least half the 400ml cartridge on the tubes with both the top bearings needing the most "pumps".
The change on my way to work today was a revelation. She tips-in much more eagerly now, feels really silky smooth, changing direction really sharply.
So a big thanks to all for the thread, I had no sign of the notch at 6000miles (10kms), but still think everyone should consider this easy bit of maintenance.
By the way, I used ZX1 lithium based Grease. I also always add their micro oil to anything I own with an engine: it's brilliant. Site below if you're interested: