Yes. In accordance with the Robust Assessment Guidelines (v2.0), applicants that meet 70% of the overall requirements of the role, including all mandatory requirements, at the completion of the assessment process (i.e. post referee checks) and are first in the order of merit must be deemed suitable for the role. External candidates would not then be considered.
Assessment can take place at shortlisting, interview and when completing reference checks. There is no obligation to continue assessment beyond shortlisting (or interview, or reference checking) if it becomes evident that a candidate does not possess the required skills and/or potential for development. At that point, the assessment is complete, and the external candidates can be considered and assessed.