Squanderbug,
Thought I'd try an help you since I have a penchant for Brits and I detected British nationality in the usage of the the word "whilst".
The 'Recently Played' playlist is installed by default, so if you deleted it, there's no way to get that playlist back, until you install the next version of MC. But, you can easily recreate it by doing this:
Create a new smartlist called 'Recently Played' (or whatever you want to call it). In the search box at the top of the playlist view, enter this (verbatim):
~sort=[last played]-d ~seq ~n=100
As for the 'Recently Played' playlist showing all of your tracks because you had just imported them, I can only think of 3 explanations:
1. You unknowingly clicked the 'Recently Imported' playlist, and whilst viewing it, thought you were viewing the 'Recently Played' playlist.
2. There's a "bug" in MC that cause MC to consider recently imported tracks the same way MC consideres tracks that have actually been recently played.
3. Same as #2, but it's not a bug; MC is suppose to work that way.
Hope this helps.
Wobbley