I’m rather proud of the fact that 99.9% of the challenges I have been instructed in since 2010 have been successful – and there’s still a chance that the one lost will be reversed on appeal.
It is, in my opinion, always worth challenging HMRC in all but the most cut and dried decisions. I have found the information on the official website (HMRC’s self styled “guidance”) to be at best misleading and often down right wrong. This is particularly so because only those decisions which support HMRC’s interpretation of the law are cited. These are often out of date and are usually first instance decision which bind no one.
When you receive a decision you don’t like, think at the very least about taking a second opinion from your accountant (or even me!).