Will cancelling my ED visa affect my ability to re-enter Thailand visa-free as a British citizen?

I'm not sure what to do here. I'm on a 9-month ED visa (extendable every 3 months at my immigration office on Phangan Island). I've attended every lesson (twice each week), and the language school is very happy with my progress.

Now I've been offered a teaching job back in Myanmar, and here's the problem: If I cancel my ED visa before I leave for Myanmar, will I have problems getting back into Thailand at a later date using a visa-free-entry (I'm British)? I'm still renting a house on Koh Phangan and will need to return from Myanmar around Christmas for a short visit to collect my personal items and end the house rental contract.

If I have my return ticket back to Myanmar, will I have any problems to enter Thailand if I previously cancelled my ED visa 'correctly' next week before leaving for Myanmar to start my new job? Thanks!