It’s really up to you and the landlord to agree. If they are struggling to lease somewhere they should be willing to be more flexible, but you need to understand why they are struggling to rent it out.
Check out business rates cost as well. The rateable value of a premises should be on the business rates section of the gov.UK website. Look into small business rate relief and whether that may change with a change of use.
The number of people I meet setting up a business who completely forget potential rates costs is astonishing, especially now cash strapped councils are getting harder with discretionary reliefs.