Still working on this. I have the gridfill, the message and the defence and am pursuing the 30. I can’t see how using the “other stuff” would illustrate “direct compliance with the instruction”.
Thank you drxx, your post got me thinking laterally and I found the answers almost straight away. Quite one of the most obscure themes I can remember but at least it's given me a phrase to confound and amuse the grandchildren.
Finally stumbled over the finishing line:-) It's not been a great weekend due to pulling a muscle in my back but this really cheered me up - big thanks to JFD
Yes, crates, sorry for delayed reply; grid filled, found the origin story and the two words - I think! Puzzling over creatures and household artefacts....