hello again aryM, I did went back to the Philippines when I resigned, cause I timed my holiday back home at that time when i'm up with my leave of absence but you can do it through writing a letter also through channel like writing to the school principal and to the school's division superintendent where you belong to, you can ask someone from your family to follow up it then, cause i know your thinking also of your gsis and other stuff. Just leave them a power of attorney so that they can transact in your behalf.
As well as my husband writing a sponsorship letter/covering letter i did write one myself also stating that i will resign once visa will be granted and I'm settled in the uk.