It's hard to comment in detail without knowing the exact contents of the exchanges. So the following are general points, and may not apply in detail.
Getting the balance right between council and clerk is not always easy. In principle, the council must set policies and make important decisions. The clerk should be left to implement the council's decisions, and a council is inefficient and inflexible if it does not delegate routine decision making to the clerk. For clarity and audit trail, this should be done through formal council decisions.
As a former clerk, I'm aware of how it can be difficult to hold a council to behaving within the law. It is also upsetting when councillors try to do the clerk's job. As a councillor, I'm also aware of how important it is for the clerk to function efficiently and to concentrate on service delivery.
Gettting down to questions of information, councillors must have access to the information they need to do their work. The clerk should cooperate in this. At the same time, the clerk is not obliged to provide information arbitrarily and is entitled to require good reasons. Some information should be more readily than others - for example bank statements or council minutes should never be withheld. Other cases may be more difficult. Given the description of the case, it sounds as if the clerk could have been more helpful more quickly.