Его можно использовать как богатый (изобильный, неисчерпаемый) источник для тех, кому недостаточно того, что может предложить NHS.

Вроде-бы, в стиле

...

С учетом расширенного медицинско-законодательного контекста:

Another consequence of the human rights act in medical law is that the judicial scrutiny of decisions made by public bodies has become more rigorous and the emphasis has moved away from the duty of the public body to the right of the individual. This change has been explained by the Lord Chancellor, Lord Irvine, who stated; ‘The court’s decisions will be based on a more overtly principled, and perhaps moral, basis. The court will look at the positive right. It will only accept an interference with that right where a justification, allowed under the convention is made out … It will need to be satisfied that the interference with protected right is justified in the public interests in a free democratic society. Moreover, the courts will in this area have to apply the convention principle of proportionality.’ Proportionality replaced the previous test of Wednesbury ‘unreasonableness’. It has three elements: firstly there must be a legitimate aim, such as, the protection of public health; secondly, it must be necessary, that is, it could not have been achieved by a method which was less invasive of individual rights; and finally, the degree of infringement of the individual’s right must be justified and no greater than is necessary to achieve the legitimate aim. A further consequence of human rights in medical law is that is possible ‘primary legislation and subordinate legislation must be read and given effect in a way which is compatible with the convention rights.’ The Human Rights Act has been hailed as the biggest legal and constitutional reform since the 1689 Bill of Rights. It could provide fertile ground for those dissatisfied with what the NHS has to offer. The Act has appeared in several health law cases over the past couple of years, its significance makes it essential that NHS bodies understand and consider the possible implications of the legislation. The incorporation of the European Convention of Human Rights gives various rights to individuals such as rights to life, to liberty and security of the person, to respect for private and family life and to freedom from torture or inhuman and degrading punishment. All these consequences of the Human Rights Act clearly shows that it plays a major role in modern health care law.

Думается, можно перевести fertile ground иносказательно.

Здесь, имхо, fertile ground употребляется в значении "питательная среда". Однако это словосочетание не очень вписывается в структуру фразы. Попробуем по-другому, например:

Считается, что Закон о правах человека знаменует собой крупнейшую правовую и конституционную реформу со времен Билля о правах от 1689 года. Можно сказать, это питательный бальзам на раны тех, кто не удовлетворен работой Национальной службы здравоохранения (или: услугами (качеством услуг), предлагаемыми(-ых) НСЗ).

Имхо, как и обычно.