Merging or removal of titles

I own a property with a freehold title and two leaseholds (head and underlease) - I own all three titles. I am in the process of selling and the buyer wants the titles merged or leaseholds removed from the title. Can you advise how long does this process can take to complete?

Emily - wait times are lengthy so once submitted you should request expedition - https://www.gov.uk/guidance/request-an-expedite

Thank you Adam, I’ll let my solicitor know.