In case this is useful to anyone else, I recently bought
Universal Micro Vacuum Cleaner Mini Tool Kit With Precision Cleaning Attachments
from ebay for just over £6
It doesn't fit perfectly onto my Dyson, but close enough and I was able to clean out all the fluff from my overlocker that I couldn't reach with the normal Dyson attachments. Also good for computer keyboards and any other small fiddly things.