Buying leasehold flat - confusion over sublet clause in lease

Hi everyone,

I'm looking to buy a 2 bed flat in London and have had survey done etc. and have got the lease through from the solicitors. The original plan was to rent out the 2nd room to help with the mortgage, but I'm not sure I can do this now given some clauses in the legal documents. I will list them below, I'd appreciate it if you guys could give me advice as to what these clauses mean exactly for me and what my options would be. Thank you!!

In the Freehold Lease document:

"...but to use the buildings for residential purposes only PROVIDED ALWAYS that each dwellinghouse and each flat shall be used in single occupation by one family only and for no other purpose whatsoever."

In the Leasehold Underlease document:

"...Not to use or occupy or permit the Flat to be used or occupied for any purpose whatsoever other than as a private residence in the occupation of a single family..."

In the Legal Report document:

"You can sublet the whole (not part) of the property, but will need to serve notice on the Landlord or Management Company..."

Thanks very much guys!!