You can claim back anything you want as a legitimate business expense. It just depends whether you feel comfortable being sort of 'out' to HMRC. They honestly don't give a shit as long as you pay your taxes. I think it was Amy who said that you could tell them you were a painter & decorator, and that you choose to use condoms to cover your brushes to keep them clean in the toolbox, and that would be perfectly justifiable and claimable.
I am down as an Alternative Therapist and Freelance Writer, and I am soon going to add Webcam Services to that list to justify adultwork advertising costs, and lingerie/toys.