Speed being of the essence with this project, I decided to spray paint the MDF. A quick coat of Halfords grey primer was followed by a trip out to buy a couple of cans of the same companies satin black. After a cup of tea, I shot this all over the stand and dried it with a hair drier.
A little bit of rubbing down, followed by more paint and the jobs a good'un.
To ensure I left with the same number of models as I arrived, each is wired down with soft iron wire pushed through a couple of holes, over each axle and then twisted together using a pin vice. Now I can turn the stand upside down and everything stays put.
The finishing touch was to print some labels explaining what each scale was and a title card jauntily stuck to the top of the "tree".
On the stand it all looked great an attracted a lot of interest from both those who didn't know much about the various scales and people who thought they did but realised they didn't know all of them.