| Ohlins chage their seals a year or so ago. They now have a dust cover flange as well as two seal flanges (or whatever the correct terminology is- time to wake up Shazaam I think!). Like most rubber compounds they are prone to damage so the dust cover helps, plus they will harden over time especially if used intermittently.
Kais did mine for £100 off the bike. Kais I have always found to be excellent. | 
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