Alex said <<<I've just acquired a MIDI keyboard, and am amazed at the horrible accuracy when recording my playing>>>

This is a function mainly of speed of response of your computer, I guess coupled with lag times and also human beings' tendency not to play exactly like clockwork. I actually went back to manual input for most things, though MIDI keyboard is superb for notating arpeggios and chords.

<<<Is there a way of "suggesting" that a bit of tempo rubato is appropriate? How do I avoid my slight tempo slips giving me demi hemi demi semi quavers(!?) >>>

YES! That is, if I understand your question. You want your "near enough" (timewise) notes to notate exactly, right? In Tools | Options, there is an Import Tab which is used by the record function (record actually records firstly into a "raw" midi stream, and then imports that stream). Simply adjust the note resolution to what you feel is the best compromise between accuracy and embarrassment! ;-) If you're only getting hemi demi semi quavers, then you shouldn't have to adjust too far!

Regards,

Andrew