I don't care that it was only temporary, I couldn't take having that bloody bit of MDF in my lounge. It had to go! I had a closer look at the feet of the TT and they are actually made of a sorbothane type material anyway, so the feet I bought were superfluous. The CDP has good isolation feet, itself, too. So, I thought: let's try this:
Now that's better!
Flukily, the deck is now dead level on both axis (and yes, it was checked with a level), when it was a bit off whent was on the MDF.
As an added bonus, it actually sounds better now. Tighter and clearer. It's a Win Win. Nice!