you’ve agreed to buy the property, the seller has agreed to sell so surely you just need the contract, why is it only a draft version? in the final mountain of paperwork that makes up a property transaction the contract is a short document which says little more than i am buying from you and you are selling to me and it will all happen for £x on this date. you might need to get a mortgage organized. if you are buying a leasehold property you might want to see the service charge payments for the last few years to check how much it costs to live there. that could be expensive so you might want to add that if the costs are more than £y the seller will pay a contribution of £z. you and the seller might agree to split the difference but that means the price needs to be changed.