Before I reclaimed VAT on training for my CPL(H), I phoned my local VAT office to check that it was legal. I explained that I was a PPL(H), was training for my CPL(H), and intended to be self-employed as an instructor after that. I still remember the conversation...
"Some types of training you can reclaim and some not. Helicopter instructing? Ooo, no-one's ever asked about that; I'll have to look it up... Here we are... Yes, you can definitely claim it back."
She then gave me the time limits, which I don't remember, as this was back in 2002 or thereabouts. So of course, things may have changed since then. If they haven't, it's legal.
But of course, it would be sensible to check with your VAT office first rather than believing anything you read on PPRuNe.