I think we are being taken for a ride.
Over the weekend, Stella has successfully got in through the catflap, thereby proving that it still works. Lil, however, has singularly failed, although she did make a half-hearted attempt yesterday. It could be that she has a problem with her jowls and they obscure her magnetic mouse somewhat, but I'm not convinced.
Grand ideas for retraining have failed due to despondency over yesterday's footie and lethargy due to today's extreme weather. Sadly, a thunderstorm wasn't enough to make Lil try to get in since the elderflower provided a more than adequate shelter.