She looked at the plans again and asked the solicitor why the boundary line was at the front door of the house, excluding the front garden, and whether there was an absolute right of access to the house down the private path.
The exchange of contracts was postponed and the solicitor later reported back that it was unclear who did own the front garden and alley.
Built as properties for letting, the houses in the lane were sold off early this century, but with the ownership of the gardens and the alley retained by the house-builder. When he died, no arrangements were made to transfer the ownership.
The problem is not just with old properties. A spokesman for the Halifax Building Society warns that builders are increasingly keeping part of a property back as a 'ransom strip', which prevents proper access to the property. The builder may then come back and ask for more money to release it.
Ms Grayson's solicitor also represented the Yorkshire Building Society, and its offer of a mortgage on the property was withdrawn unless indemnity insurance was arranged. Not wishing to inherit the problem, and considering it the vendor's responsibility, Ms Grayson did not pursue the purchase.
George Pope, a surveyor at John D Wood & Co, stressed that checking a property's title is the domain of the buyer's solicitor: 'We haven't got the time, and we're not paid the money to do these things. Conveyancing is terribly simple, except when something like this turns up.'
Oliver Paine, Chairman of the Law Society's Property Committee, said that problems of title were rare 'unless there is other land nearby to develop. The answer is to look at the plan and if you're not happy compared with what's on the ground, then ask questions. Nowadays there is a plan for every piece of registered land.'
The problem of right of access through another person's land is more common. House owners do have prescriptive rights once a path has been used for access for more than 20 years. Mr Paine added: 'If it is your only way in then you can prove you have a right of way of necessity.'
The spokesman for the Halifax confirmed that it was normal for a lender to ask for assurances that a buyer would have full legal rights over a property.
'They must have a legal right of access, and they must have a legal right to use all the utility services that are there. If they don't, the society would withdraw its mortgage,' he said.
'The borrower can take out defective title indemnity insurance, but it is the solicitor's responsibility to make sure that it is all correct, and if he or she fails to do this then the buyer can claim against the solicitor for negligence.'
Alan Norris, a broker with Adams Brothers, a legal contingency insurer, said: 'The cost of insuring against defective title depends on the defect, and on the value of the property. To insure the right of access the premium would start at 0.2 per cent of the property value. If there was a question over the right of ownership of a garden it might cost about 0.5 per cent of the value.' The premium is paid only once and the policy is held in perpetuity, meaning that future owners of the property will also be insured. If there was a claim, the insurer would pay for any legal costs and would also either pay to purchase the plot of land, or make up the difference in value represented by the loss of land.