Mira 88 still dripping?

I have a dripping Mira 88 surface mounted shower valve. It had stood unused and seized for about 2-3 years, then I rebuilt the shower, and freed it up, but ti dripped, so I bought the service kit and replaced all the o-rings and the central brass flow spindle, I de-calcified everything too. It stopped dripping for one night until it was used again, and now its still dripping as before.
How can this be? Any help?