Thanks for the replies.
I've been sent this from a contract used by ABC Leisure Group in Alvechurch, which seems more reasonable? Also, arranging and paying for surveyor/boat yard should indicate I'm serious about taking this further in my mind.
Following the survey, the Purchaser may, at his/her sole discretion, by written notice to the Broker, either: 5.2.1 reject the Vessel outright; or 5.2.2 reject the Vessel but offer to proceed with the purchase ...... (a) to rectify specific listed defects or deficiencies in the Vessel or the Inventory before Completion; or (b) to a reduction in the Purchase Price to enable the Purchaser to rectify such defects or deficiencies after Completion.