Hmmm, decisions, decisions. I am in the process of doing other things to the bike and have the padded shorts but I still find the constant vibration painful

to the point where I need to do something about it.
If it's real pain you are talking about maybe you have the wrong saddle or have it fitted incorrectly.
As for Andy M being ruined by his saddle for a month, I wouldn't advocate letting a saddle cause pain as a way of tanning it. Strikes me as a somewhat old-fashioned, not to say dangerous approach.
I must say I never found that my suspension seatpost caused any pedalling problems, much as it seems odd to have your position moving however slightly, relative to the pedals.
But I still think they are superfluous for on-road/mild off road such as canal paths. I think if you are hitting potholes I think it's good practice to move with the bike/use your legs as suspension by standing slightly rather than using the seatpost to help.