Contacted the lawyer that organized the Chanot 5 years ago.  She will charge us 10,000 baht and will bring a representative to the land office to make sure we are not ripped off.  

 

We spent 3 days with this lawyer back then and she came with a good reputation from a rich friend who did 4 or 5 projects with her so my "trust" level is reasonably high.

 

Will provide details as I get them.

Amazingly some land markers have a tendency to move around and some have the ability to disappear entirely. Having said that, they are referenced by a centralized geodesic reference which is annotated on the chanote.

The neighbors motives should be regarded as questionable regarding fairness and what you do depends upon how much you're prepared to lose.

If validity is important to you, trusting some Joey Bagodonuts to fulfill your expectations could be a big mistake.

My wife's grandmother recently subdivided property for her kids.  Grandma, kids, and land office rep were all present to locate the markers.  If the same process is followed in Samui, your neighbors are equally as responsible for the placement of their markers as you are for yours.  Suggest you hire a rep you can trust and make a date with the neighbors to make the survey together with the land office rep.  

You might need to also hire a worker to cut the brush.  All that still  might likely be cheaper than flying back from Canada!  

If you need more time get a lawyer to throw a monkey wrench into the process.  It seems to be going pretty quickly for Thai bureaucracy.  

Good luck!