Marius wrote: Not to throw spanners in the works but my one A seemanni sling forgets how to spider.

This has happened twice:
Spider closes up burrow to molt.
Doesn't open burrow up again after and just sits there - where the others have opened up and are feeding.
Over the weeks the abdomen gets ridiculously small, almost disappears, so I bore down, careful not to injure the spider, and drop in a roach which the spider immediately attacks.
Rinse, repeat.

I honestly believe that if I didn't do this it would die.