S.84 of the Law of Property Act 1925 covers how and when the Upper Tribunal can discharge or modify a covenant affecting land. I have reproduced s.84(1) and (1A) below. Seems to me the battle lines are drawn around s.84(1)(aa). I can't see s.84(1)(a) applying and 84(1)(b) definitely doesn't apply. 84(1)© might apply but it's very simmilar to 84(1)(aa) apart from the public interest point. I don't know whether a public interest argument would be a runner in the case of a private nursery so my money's on the argument that there is no genuine practical benefit to the objectors that cannot be overcome by throwing some cash at them. No idea whether that's a winning argument though. I still think that Piplings have done themseleves no favours by opening for business before doing all their homework - they shoudl have made their application to the Upper Tribunal before they even went anywhere near planning applications.

s.84 Power to discharge or modify restrictive covenants affecting land

[(1) The [Upper Tribunal] shall (without prejudice to any concurrent jurisdiction of the court) have power from time to time, on the application of any person interested in any freehold land affected by any restriction arising under covenant or otherwise as to the user thereof or the building thereon, by order wholly or partially to discharge or modify any such restriction on being satisfied—

(a) that by reason of changes in the character of the property or the neighbourhood or other circumstances of the case which the [Upper Tribunal] may deem material, the restriction ought to be deemed obsolete; or

(aa) that (in a case falling within subsection (1A) below) the continued existence thereof would impede some reasonable user of the land for public or private purposes or, as the case may be, would unless modified so impede such user; or

(b) that the persons of full age and capacity for the time being or from time to time entitled to the benefit of the restriction, whether in respect of estates in fee simple or any lesser estates or interests in the property to which the benefit of the restriction is annexed, have agreed, either expressly or by implication, by their acts or omissions, to the same being discharged or modified; or

© that the proposed discharge or modification will not injure the persons entitled to the benefit of the restriction;

and an order discharging or modifying a restriction under this subsection may direct the applicant to pay to any person entitled to the benefit of the restriction such sum by way of consideration as the Tribunal may think it just to award under one, but not both, of the following heads, that is to say, either—

(i) a sum to make up for any loss or disadvantage suffered by that person in consequence of the discharge or modification; or

(ii) a sum to make up for any effect which the restriction had, at the time when it was imposed, in reducing the consideration then received for the land affected by it.

(1A) Subsection (1)(aa) above authorises the discharge or modification of a restriction by reference to its impeding some reasonable user of land in any case in which the [Upper Tribunal] is satisfied that the restriction, in impeding that user, either—

(a) does not secure to persons entitled to the benefit of it any practical benefits of substantial value or advantage to them; or

(b) is contrary to the public interest;

and that money will be an adequate compensation for the loss or disadvantage (if any) which any such person will suffer from the discharge or modification.

(1B) In determining whether a case is one falling within subsection (1A) above, and in determining whether (in any such case or otherwise) a restriction ought to be discharged or modified, the [Upper Tribunal] shall take into account the development plan and any declared or ascertainable pattern for the grant or refusal of planning permissions in the relevant areas, as well as the period at which and context in which the restriction was created or imposed and any other material circumstances.

(1C) It is hereby declared that the power conferred by this section to modify a restriction includes power to add such further provisions restricting the user of or the building on the land affected as appear to the [Upper Tribunal] to be reasonable in view of the relaxation of the existing provisions, and as may be accepted by the applicant; and the [Upper Tribunal] may accordingly refuse to modify a restriction without some such addition.