ChD 24 July 1986. Originating summons by N seeking declarations in favour of their claim to proceed with a rent review . S counterclaimed. The 21-year lease with provision for an upward only rent review; a trigger notice to be served "at any one time" after 14 years. The 14th year commenced on 29 September 1981. On 27 August 1982 a letter was sent by N`s surveyors stating that they had been instructed to negotiate the rent review effective as at 29 September 1982, proposing a rent of £11,500. S invited negotiations which were unsuccessful. If no agreement was reached within 3 months the landlords could require reference to a third party surveyor by giving notice 3 months thereafter. This notice was not served within the time limit . S argued that N had lost its chance to have the rent increased. In June 1983 N`s solicitors wrote, enclosing a second trigger notice, followed by a notice requiring reference to an expert which was served within the time limit. At issue was whether the re