Do I need to cancel my work extension with immigration if I am leaving my teaching job and the country by June 30th?

I’m sorry if this is a stupid question but I wanted to check. I understand the requirement to go to immigration to cancel your work extension if you leave your job earlier than your extensions date of permission to stay. However I will come to the end of my teaching contract on June 30th. My extension was given until the end of my contract June 30th. I am not renewing my contract and will be leaving the country to go back to UK to apply for an OA visa at the end of June. The school will return work permit (which also runs out on 30th June.

Am I right in thinking I do not need to go to immigration before I leave? Thanks.