Please help!

I have an ED visa but all the renewal stamps are used up now. I am on the last one which ends on 12th July. I am waiting for my business to be registered etc and there have been delays, hence the panic.

Can I:

Option A) Get a 7 day extension inside Thailand at my closest immigration office (Samui for me)

Option B) Get X days on arrival by going out and in again at the Satun Malaysian border (where I usually go for a bounce)

Option C) Something else magical and inexpensive that I never heard of?

I am a Brit with a Brit passport. To add some extra excitement, I just received my passport renewal so my expiring visa is in the old one and I don't see the point in having it transferred. Please also advise if I am wrong about that?

TIA!!!