Does upstairs freeholder need agreement from us to carry out work?

[Dave007]

We live in a ground floor leasehold Victorian flat.

As well as their majority leasehold, our upstairs neighbours own the freehold for the whole 2 flat property (their flat and ours).

They are planning on doing some major work upstairs (loft conversion) and will need to put scaffolding in our garden (demised to us).

Do you know if they require a party wall agreement from us or any other agreement in order to complete this work?

[Peridot]

The party wall is adjoining wall between neighbours, generally terraced and semi's. Although loft conversions would often be a situation where it would be recommended an agreement be entered into this is for the neighbours either side not below. Other than asking to put up scaffolding is there any part of your properrty that abuts their other than the ceiling?
It may be sensible to speak to a surveyor just to check but I wouldn't have thought it necessary unless the neighbour is putting new foundations on your boundary (even if garden) for example.
There may be others along who have more experience of this area than I do but if not do find a local surveyor to call and ask to be sure.