Matt,
It's really annoying as the noise only started happening around 8-9 months ago ... It doesn't get any quieter with the clutch in, which leads me to believe it's not clutch or Flywheel related ...
Mine does the same, I just had my clutch and flywheel changed (not to try and fix this, just because they needed doing) and it's made no difference, so it's not either of those.
I find the most annoying bit is when people point it out to you "mate your car sounds like it needs an oil change" "Nope, it's not that the oil was changed a 100 miles ago"