Mark. I’ve just come back to uk. Been for 75 days. 2 nd day there I got my 30 days added. Was very easy. Print form off the internet. Fill in. 2 passport pics. Passport. Evidence of residency. 1900 baht . Was in and out in 45 mins. Passport stamped !
That was phuket. May be different in other offices? Just sharing my experience 👍 best of luck.