It has been 4 long weeks for me. Am worried that I might have to do an exhausting and expensive Visa run due to delays outside my control.

Are you getting a Thai police clearance letter?

I applied for a Thai police clearance letter so I could work in another country due to the length of time I have lived in Thailand now. They gave a date when it would be mailed to me and it arrived 3 weeks early. Their date was 6 weeks from the application date

You should have collected it in person. Only took about 4-5weeks... I got one sent to Ireland before and it took three months! Good Luck...

Two weeks exactly, I went and picked it up