Readers' forum: Farm partnership

I read with interest ‘Readers’ forum: Goods for own use’ in Taxation (4 July) which concerned trading stock items that are taken for personal use. I would like to extend this query to trades where the exact goods being taken are more difficult to define. 

I act for a client who owns a farm in partnership which has diversified into liveries. As is frequent in farming the trading is carried out by brothers who do not always agree with each other and neither do their respective spouses.

One spouse of the partners runs the livery and has six private horses with a number of young and retired horses. The brother with no horses considers this should be attributable to private use for the accounts and the tax returns. The other brother argues that because his wife pays for all the feed and haylage for her own horses...