ChD 22 March 1989. Originating summons by landlords (L) seeking a determination on the true construction of part of a rent review clause relating to premises on an industrial estate. The tenants, (T), counterclaimed, seeking rectification of the lease on the grounds of common or unilateral mistake, should the interpretation be favourable to L. The dispute centred on definition of "Standard Warehouse Building", the hypothetical building by reference to which the rent was to be determined at review. The definition was general and gave no guidance as to the size of the yard area surrounding the building. In T`s case the open yard space was 1.75 acres, more than three times the normal size of conventional warehouse yard areas on the estate. L submitted that in determining the rent at review, the 1.75 acres should be taken into account. T contended that the area should be assumed to be half an acre only, in line with the lease, which referred to conventional yards on the estate. ChD decid