[2003] EWCA Civ 1760 CA, 4 December 2003. Appellant M acquired the freehold reversion of a block of flats occupied by the respondent tenants T, who had not been given first refusal by the previous owner as required by the Landlord and Tenant Act 1987 Part I before the sale to M. T served notice on M under s11A of the Act to trigger their right to purchase the property. M queried the validity of the notice because it had failed to state the addresses of T's flats as required by s54(2). T brought proceedings against M for failing to respond to their notice in time for them to exercise their right to purchase. The judge dismissed M's invalid notice claim, stating that M had been made aware of the addresses and the s54 requirement was not mandatory. Appeal on the issue whether that requirement was mandatory or directory. "Held": appeal dismissed. The notice was valid. The substantive provisions here were the right to acquire the freehold. The s11A notice and s54 statement of addresses were secondary or machinery requirements, of which the notice was essential machinery and the s54 requirement merely supportive.