Hi Andrew (and MTZER if you are still listening).
I too have a Dahon Speed Pro with a Pantour hub in which the elastomer has failed.
I have a couple of questions. about replacing the elastomer.
First, I assume the Thudbuster LT elastome you were suggesting is the seatpost elastomer sold by Crane Creek?
Nowadays, these do not seem to be sold be sold by color - they are all black - they just describe the various types as "firm", "extra firm", "medium", "soft" etc.
Do you happen to know what firmness the blue elastomer was?

Second question, the pantour suspension hub owners manual I found online shows a couple of large spacers/washers on either side of the hub (they are labelled 4 & 5 in the owners manual, if you have access to it) these seem to be missing from the hub I have, and there is some side-to-side play of the hub on the two "axles" (though the bearings themselves do not seem to be worn). Do you have those specers in your hub, and what are they made from? I thought might replace them with something like felt, to provide a seal, but that might be entirely the wrong idea. Any thoughts or suggestions gratefully received.