ChD 21 March 1991. Concerned the construction of a rent review clause in a lease. The expert, a chartered accountant, decided in favour of the construction contended for by the landlords and the decision was challenged by the tenants. The case centred around the principles governing the challenge to a decision of an expert, and the Judge was bound by the CA decision in Jones v Sherwood Computer Services Ltd . The formula for calculation of the reviewed rent produced by the tenants relied upon a calculation based upon the average room rate ; the rent produced being £422,359.15. The rent contended by the landlords was based on room prices made available to the public, which produced a rent of £597,315.14. The tenants took out an originating summons challenged the experts determination, maintaining it was a nullity as based on a misconstruction of the expression "average room rate". Applying the principles of the Jones case, the question was whether the expert had assessed the wrong sub