I stripped down my '09 ATA Micros today and managed to diagnose and temporarily fix the stuck down issue that is common with several models of Marzocchis. Reading up online the proper fix needs a slightly thicker O-ring than fitted. Any suggestions on where I could source a specific O-ring? CRC and Wiggle don't seem to do them. I've emailed the distributor but as it's a bit of a hack they may only have the original size.
If you could get the exact dims, I'd be tempted to talk to someone like
Vulcan Engineering (they have an office with stock (can see it from the bus window) on Archer Road) - Orings are O rings surely?
(just like the stuff Muc Off and Finish Line sell can be got for £1 from ebay)
Assuming that the fix is a simple job of course, if not then fatdoc definitely knows more than I do, to the power of infinity