According to the Hambleton District Council Planning website, the Application is under appeal, and no final decision has been announced, so I find it suprising that the Council would seek to enforce a planning notice while this was the case.
It depends how much the applicant is taking the ****.
If they've applied for permission for something, and been turned down, and then gone and built it anyway, then the answer to "how much" is "a lot". It would be perfectly in order for the council to issue an enforcement notice.
In fact it's not that unusual for all the following to be in progress at once:
(1) An original application, which has been turned down, and is now under appeal.
(2) An enforcement notice, which is also under appeal.
(3) A new, retrospective, application.
The point is that an applicant who is taking the **** cannot put off enforcement forever just by, for example, putting in an endless string of repetitive retrospective applications, appealing each one, and them claiming enforcement should not occur "because our application is under appeal".
There is, unfortunately, no way in law to stop a silly series of repetitive applications, provided the applicant is willing to pay the fees for each one, so sometimes you have no remaining options but to go for enforcement.
Will council officers be held to account for squandering of public money pursuing frivolous and misguided proceedings
That'll be up to the appeal inspector and then the local government ombudsman.
If he decides that the council's decision was completely haywire, and had no reasonable basis, the appeal inspector can award costs against the applicant. You could them complain to the ombudsman and try to get him to go after the councillors (with, I suspect, limited propsect of success).
If on the other hand the appeal inspector decides that the council made a reasonable decision, but he happens to have come to a different reasonable decision and allows the appeal, he will make no order for costs and no complaint to the ombudsman has any chance at all.
Where is the logic of elected officials closing down or attempting to close down a business that supplies employment and revenue in a rural area?
Those are not reasons in planning law that can be taken into account when considering a planning application.
The answer to your question is thus "planning law (like, in fact, any other law) is not based on, and does not have to obey, logic".