CPR 36.17(4) applies where a Claimant beats its own Part 36 Offer in substantive proceedings bringing with it various rewards including a 10% uplift, enhanced interest and indemnity costs. The question to be addressed in this case was whether it applies equally to the costs of detailed assessment i.e. can you make a valid Part 36 Offer in respect of the costs of the detailed assessment proceedings and reap those same rewards if it is beaten? In other words, do the the costs of the detailed assessment proceedings, for the purposes of CPR 36.17(4), fall within “any issue that arises in the claim”?