D&F. As I understand the law (I spoke to the tax office that dealt with my tax when I had the same query) it is not allowed on training that is undertaken as a distinct course as opposed to training that undertaken as part of performing your daily duty. I'm not sure that I explained it very well, but phone your tax office for a full, and definitive explanation.
However during that conversation I was able to ascertain that as I had recently bought a new computer I could claim a proportion of it's value as a business expense, and claim it's depreciation against my tax code. I asked if 75% of the value was considered reasonable, and that was accepted. You might like to ask about that when you phone them up.
They can be quite helpful if you play them right!