Excellent replies, folk; many thanks. It is, indeed, now available in the 'Animation Mixer'. A previous Project had this change updated automatically upon importation; it was only when treating a new animation that I noticed this apparent absence. A closer look revealed the amazing truth : it's there, but moved..!
Note to self : have my spectacles checked.
Thanks for the rapid replies; case closed.
Edit : I spoke too soon. Where it was relatively easy before to import and use animations (from Blender, for me...), it will now require a few more evenings with an ice-pack and a tube of aspirins. I shall doubtless be able to get these insects moving again, it will be by using a pneumatic drill to open a hazel nut, compared to the previous method. 'Sigh' At my great age, will I even be able to finish this (rather simple...) game I'm making..? The jury is out. It was all going so well. I'm not eager to go back to v4.1, but the time spent working out this new 'challenge' is time I don't really have. Oh well... :-(