60 Mr Magann had no difficulty in assessing injurious affection in the order of 10% for noise, dust and loss of privacy impacts based on his expertise and experience without being able to point to any specific sale that would support that estimate. Yet he did not accept the validity of any equivalent attempt to estimate the enhancement of value consequent upon changing the access to the respondents' property from an illegal arrangement dependent on the continued goodwill of other landowners to legal access available in perpetuity. His reasons for not doing so were unconvincing. First, and as Mr Banwell recognised, the fact that the respondents have not been denied access for seven yeas does not alter the essential difference between a property with legal access and one without. The risks associated with the illegal access in a context where ownership of other properties may change over time are obvious. In this case, ownership of many of the affected properties has changed. Secondly, the idea that illegal access can readily be rectified without too much cost and time is unrealistic. It fails to appreciate the risks inherent in proprietary relationships. Thirdly, the lack of comparable sales to isolate the effects of illegal access on value is neither surprising nor any bar to the valuer providing useful opinions on the issue. As the Privy Council observed in The Secretary of State for Foreign Affairs v Charlesworth, Pilling & Co [1901] AC 373 at 391:
It is quite true that in all valuations, judicial or other, there must be room for inferences and inclinations of opinion which, being more or less conjectural, are difficult to reduce to exact reasoning or to explain to others. Everyone who has gone through the process is aware of this lack of demonstrative proof in his own mind, and knows that every expert witness called before him has had his own set of conjectures, of more or less weight according to his experience and personal sagacity. In such an inquiry as the present, relating to subjects abounding with uncertainties and on which there is little experience, there is more than ordinary room for such guesswork; and it would be very unfair to require an exact exposition of reasons for the conclusions arrived at.