When I bought the bike I noticed that there was little to no rebound damping on the rear end. Once home and up on the bench it was clear that the shock was leaking! 
This bike would have been horrible to ride not to mention a touch dangerous!
I pulled out the rear shock (I had wanted to service the rocker arm bearings and the link rod anyway ) and removed the spring, to get a closer look and to my surprise the chrome on the rod looked to be in good condition āyesā 
, all was not lost, just maybe the light at the end of the tunnel had been switched back on!
I have worked with shocks a lot in the past and still keep a cylinder of Nitrogen in the workshop. Now to find a seal kit, I received a fairly negative response from two Ducati dealers 
so a change of tack was called for, most motor cross Showa rear shocks are serviceable so I started to search for a suitable Honda crosser that used a 16mm rod in the shock, one call and Ā£10 hit in the handbag later and the seal kit was on its way. Home from work next day to find jiffy bag with seal kit genuine Honda/ Showa part inc dust seal, 2 part oil seal and seal block bumper. 
I should point out that the units are charged with approximately 10bar of Nitrogen! and are ānot to be played with until the gas is releasedā 
So to stop this tale getting too much longer I stripped and rebuilt the rear shock for under Ā£20 quid 
well almost it costās me the best part of a Ā£100 quid a year for my Nitrogen cylinder. 
Happy Days
Esme
) can be found for under Ā£3 each if you buy 10 at a time, when genuine Ducati parts are around three times the price.