Well, I think we have made progress and potentially found the cause of the problem.
After a couple of skipped meals, we gave Fudge a small meal and then a number of hours later she was a bit sick which included a very naughty bit of wood (eek). Typically she chose a bad time (4am) and place (on the carpet under the bed - right in the middle)

Since then she has been a bit more interested in her food, so fingers crossed all the wood is gone. I just need to grow eyes in the back of my head so I can stop her from eating any more rubbish.

One thing I wanted to check, do you mix the yuk anuba with tinned Chappie? If so, that's a big no no. Never mix tinned food with a complete food - only mix with a mixer biscuit.
Hands up I do mix the two, but literally only one forkful of Chappie to make it a tad more 'interesting'. I've not really had problems with any of my dogs having digestive problems, they've always 'done' really well. Maybe I'm just lucky.
Thanks for all the inputs.
