When was the last performance appraisal?
What did it say?
Is the employee likely to “want” to depart or are they more likely to contest? (I bet I know the answer to that even if you don’t!!)
Unless you can arrive at a mutually agreeable settlement, your only option is restoring efficiency and effective appraisal processes which will either lead to professional improvement OR dismissal.
I would suggest the council cannot realistically expect to justify the use of public money to “settle” an unsatisfactory employment supervision situation since it is the council which has allowed this situation to degenerate which should not be an expense to the public fund.
To answer the direct question - yes I do have experience (Jun 23) of dismissal gross misconduct for the clerk but it took about 12 months to get there.
Prior to this clerk being dismissed, the previous clerk was “terminated” by the previous council under a so-called confidential severance agreement which was beneficial to both parties since it masked the employees disgraceful behaviour and it masked the council’s appalling lack of management.
Unless you have an HR expert as a Cllr you’d be better off engaging a contract HR service and follow a properly independent process.