Readers' forum: Horse trading

I act for a management consultant who is VAT registered as a sole trader. As a separate activity my client sometimes buys a share in racehorses – the hope 
being that the horse wins some races and provides a return on the investment. 
She owns a one-third share in a horse with two other people and is about to sell this to a third party – not one of the existing two investors – for £30 000.

I have told my client that this is a transfer of a part share in title to goods – and because the sale is being made in her own name this forms part of her VAT registration as a sole trader and will be subject to output tax in this case £25 000 plus £5 000 VAT. But the more I think about it I suspect...