Landlord forfeits a long lease because of rent or service charge arrears and claims a possession order. The court makes the order but either fails to give the date by which possession must be granted and/or fails to give the tenant the option of paying the arrears and costs before the date expires and thereby earning relief from forfeiture. The order is deficient and an application for it to be set aside should succeed. The form of the order the court has to make is governed by section 13 of the County Courts Act 1984. The order cannot take effect in less than four weeks and it cannot be unconditional. That's the case of Golding v Martin  EWCA Civ 446.
And here's another one a bit like the other one. Until any contractual right to a landlord to re-enter premises under a long lease has arisen the landlord cannot validly serve a notice under section 146 of the Law of Property Act 1925. In Toms v Rubbery  EWCA Civ 128, the lease provided for a default notice to be served by the landlord and 14 days for the breach to be remedied. The landlord had pounced under section 146 before the expiration of a contractual notice. He pounced too soon and so his section 146 notice was invalid and the landlord was not entitled to possession on the strength of that notice.
These cases will not impact on the majority of cases which come before the courts where forfeiture is not involved. If you are a tenant and have been the recipient of an order which you may think is deficient, obtain professional advice before launching a court challenge to the order.