How long does it take to process form OC2?

How long does it take the Land Registry to process an application for a copy of a lease? My son is purchasing his first property and the vendor's solicitor has submitted form OC2 requesting a copy of a missing lease. The lease was created in 1976. 

It would be very helpful to know how long it will take for the lease to be received by the solicitor as my son needs to know when he will be able to move into his flat. 

Thank you in advance for your help.

Helen - OC2 applications are generally processed within 48/72 hours. It's the responsibility of the landlord/tenant to hold the lease/counterpart as appropriate so I assume by 'missing' you mean that neither can find the original/counterpart and that the OC2 is to see if we hold a copy on file. 

Thank you Adam. Yes, the lease is from 1976 and no one appears to have it! The sequel lease of 2009 refers to clauses in the 1976 lease so we really do need that.