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Yes, and sue him in the County Court for all the money his incompetence has cost you and, furthermore, report his antics to his professional body, if he has one.
You will have to advise your tax office of your accountant's antics. You will not be popular as you can well imagine.
In the light of what has happened employing another accountant would be a good step forward.
I am not sure what you mean by thresholds.