When I got my little female, 6 month old, BC up this morning I noticed that she had long white threads on her bedding...I couldn't imagine what she had got hold of that would have resulted in such a mess but then I noticed...She had chewed off the white feathery tip of her tail...fortunately, she hasn't damaged the tail itself but now I am concerned as to why she might have done this...Nothing was different with her routine and she does have items that she can chew in her bed...

Anyone got any possible explanations why she might have done this and more importantly how can I prevent her from doing it again?

Firstly, have you made sure she has been wormed regularly. BC's can be one of the worst breeds for worms when they are little. I would worm every month until they are six months then once every two months until they are a year old.
This happened to my friends bc who is the litter brother of my youngster. He completely chewed off his white feathering on his tail down to the tail stump (no damage to the tail itself) This was when he was six months. Turned out he had a blockage and had eaten some flooring. The pup was still going to the loo ok but it was obviously causing some discomfort. He was given some liquid from the vet and sure enough bits of flooring came out over a two week period
I would call your vet and speak to them about it and if requested take her in for checking. A vet can find a lot of things just from a feel around of your dog.

I had a Bichon who would chew his tail if is anal glands were blocked.

Thanks I will contact the vet and take her in for a check-up