The DNO minor works are un-looping your supply you share with a neighbour and potentially a change to the cut out fuse.
The image below shows a looped supply, usually seen in older . The DNO will alter this, so you have your own supply to your property. The black box where you see cables coming in to your property has a fuse in it (the bit sticking out top left) this is the cut out. If yours is 60 or 80Amp they will upgrade it to 100A.
If your lucky they may fit a 3 phase and neutral supply which future proof your property. Having a 3n phase supply means you will be able to fit a 22kw charger when the time comes. It may be benificial if you askpromt the DNO if they are installing a 3phase supply whils’t they are there as it will be free.
The letter from your DNO suggest OVO can carry on with the install of the charger as it will not affect any minor works they need to carry out.