That is not what I said. I said there appears to be the possibility that there is duality of purpose to the trip as a whole. That can open up questions, particularly in relation to the tax position of the employer and whether such expenses are an allowable expense in relation to business income. It is not the swapping of seats that is the issue, it is the whole trip. Of course I am not an accountant and I may be very cautious in how I interpret the rules but there are specific references to allowable and disallowable trips for business income outlined within the Busines Income Manual on the HMRC website covering this exact topic.