My corporate client has sold part of its trade (an financial advisory business). The goodwill of the part business (a client list and associated commission stream) sold for £500,000. Total goodwill is valued at £1.5m. Goodwill was purchased in 2012 for £100,000 (current NBV £50,000) and a further £500,000 paid in 2016 (NBV £400,000). In addition the company has won new clients (at no cost). I am at a loss to know how to calculate the capital gain and intangible credit - is it simply by reference to relative values or do I look at the lists of individual clients originally acquired and allocate the costs appropriately (including the cost of "purchased clients" that have since been lost)? Your help will be gratefully received.