I've just contacted Crownhill, from whom I originally bought PicBasic Pro and subsequent updates up to 2.50, and of course any paperwork etc has long since turned to dust. Unfortunately they aren't able to give me any proof of purchase, as they've changed accounting systems since 2006 (was it really that long ago?).

How to proceed to purchasing an upgrade to 3 then, please?

And what happens with MCS - all I have is the CD for MicroCode Studio from Mecanique? I can't recall entering any serial number.