Consent to Let

I leasehold my current property but intend to move out and let the property. I have ben nosing through my lease and struggle for the large part to make head nor tail of it. Basically I am trying to determine if I need the landlords (countryside properties) permission prior to sub-letting the flat. The lease states as follows:

Tenants covenants:

Assignment or Sub-letting

Not to:-

transfer or assign or underlet ot part with or share possession of any part of the property (As distinct from the whole).

underlet the property otherwise with the prior consent of the landlord and the managing agents (such approval not to be unreasonably withheld or delayed) PROVIDED THAT the tenant shall be entitled to grant AST of the property for periods of one year or less containing a covenant bu the underlessee to observe and perform the covenents and conditions contained in this LEase mutatis mutandis without the need for such consent.

Then some stuff about transferring or assiing the propert for which I assume is not relevant to this scenario.

I have spoken to the managment company regarding letting and they said I didnt need to do anything.

I read it as though consent is required but would just like to be sure!