“How the character of the area and the amenities would be affected by the modification of the restriction is not in my view to be judged by envisaging the worst that could be done without breaching the restriction and comparing it with what the proposed modification is intended to permit, and indeed, as I have said, this is not Mr Fancourt’s case. In such a case as this, the provision, it seems to me, operates in this way. By preventing development that would have an adverse effect on the persons entitled to its benefit the restriction may be said to secure practical benefits to them. But if other development having adverse effects could be carried out without breaching the covenant, these practical benefits may not be of substantial value or advantage. Whether they are of substantial value or advantage is likely to depend on the degree of probability of such other development being carried out and how bad, in comparison to the applicant’s scheme, the effect of that development would be.”