Sole trader franchise fees (again!)

I can just about get my head round the idea that the franchisee is buying an invisible asset, the brand of the franchisor - although in my dimwitedness it seems to me that it is really a licence to operate which ought to be tax-deductible over the the course of the agreement.

Never mind, what does irk me is that the training isn't tax deductible either (but would be if the franchisee was a limited company). Where is the sense in that? Am I missing something obvious?
Graham Kemp