Update as promised.
So just came back from ChangW immigration. NON-B visa extension date cancelled/changed to 8th April, last day of work. No problems. Then COVID extension until 2nd May (under consideration stamp) when I have to return to immigration. No problems. I assume this is standard and then they will stamp for another 30 days? Is this right? 5 Hours in total but worth the wait. Once again thanks very, very much for all your help and advice.
TLDR : Answer Summary
The user successfully visited ChangW immigration to have their NON-B visa extension date canceled and changed to April 8, with a COVID extension granted until May 2. They are seeking confirmation on whether they will receive an additional 30 days upon their next visit, and comments from the community confirm that as long as they return at the designated time with their passport, they should receive the remaining extension days.