Section 20 of the Act of 1965 (compensation for short-term tenants) is to be read as if it were modified so as to secure that persons with such interests as are mentioned in that section are compensated in a manner corresponding to that in which they would be compensated on a compulsory purchase of the interests but taking into account only the extent (if any) of such interference with such interests as is actually caused, or likely to be caused, by the exercise of the right concerned.