Variation of lease following addition of a new Roof Window and Doorway

I have a share in a freehold for a flat where the leaseholder has placed a new Velux window in the roof and put a new doorway in an internal load bearing wall. The definitions of the retained parts in the lease define all parts of the roof as retained and also all internal load bearing walls. Will the addition of the new window in the roof and the new doorway in the internal load bearing wall constitute an increase to the demise and therefore need to be treated as a surrender and regrant if the lease is varied?

Richard - you need to read how the 'demise' itself is defined in the lease. If that detail is changing and you are varying the lease as a result then it will be a surrender and regrant scenario
If I am understanding correctly though putting a window and door into an already leased space (demise) isn't altering the extent of that demise? More likely to vary the terms of the lease itself re say access and light?

Thank you Adam. For clarity with regard to the new roof window. The roof is not part of the leased space it is defined as retained by the freehold using the following definition in the lease.

the main structure of the Building including the roof structures, the foundations, the external walls and internal load bearing walls, the structural timbers, the joists and the guttering

The change has removed part of the roof structural timbers and joists to accommodate the new window frame. The definition with regard to what parts of the ceilings and roof are part of the demise is as follows:

the ceiling plaster, plasterboard or other ceiling surface below the joists or other structural ceiling supports supporting them

Given the leaseholder has removed part of the retained roof area which is above and not below the joists would this mean an increase to the demise?

Richard - whilst it's not for us to explain/interpret such things for you it feels like the approach to this is awry.
It's not about the retained freehold detail but all about what the lease actually includes within it's demise. As such if I follow the mechanics of what a new window and new door might impact on I assume that the tenant has incorporated the roof space into their demise. If they have then that's clearly a varied extent as the roof space wasn't included but now is.
However, and this might be why you are asking, if the roof space was always in the demise and they've put in a new door to it plus window for extra light then that doesn't read as if the demise has changed as the roof space was always included
As I say not for us to explain or define but hopefully the discussion will help you and the tenant/landlord decide what's needed, if anything

Thank you Adam. That is correct, the roof space or attic is already part of the demise so I'm going to assume for now that a variation to change the plan to include the new elements won't require a surrender and regrant.