Hello and apologies for restarting what is probably an old topic. 

Can anyone who's recently been through the process give a definitive list on what documents are definitely required. For example, when I search online, some lists say you need a letter from the organisation requiring the check and others do not. 

I'm hoping you can do it with passport, photos and a copy of WP (need original sighted as well?). 

Any tips would be much appreciated. 

If you know an Internet place close by that area that does printing that would also be amazing. 

Thank you. 

Info here: http://pcscenter.sb.police.go.th/filedownload/infomation-service-4.pdf

And more info on the Police Clearance Service Center website. http://www.pcscenter.sb.police.go.th/eng/

Thanks for that. Seems very clear. 

If you are in a hurry, these people can get it in about 5 working days: https://www.a-plusservice.com/

I have used them twice and they deliver as promised. For a fee of course. I believe they charged me 4400 baht

I did one last week in Bangkok.

I am retired and from New Zealand.

I visited the Police Office that deals with these things and provided copies of my Passport ID page and copy of my Visa. I had passport style photos but they were not required as they took photos and finger prints. The process was well organised and took about 1 hour. There is a copy centre within 100 m of the police office, Although their web page says they do not stop for lunch break, the photographer did so.

Cost was 100 baht and extra 50 baht to have posted to me on Samui. Expect it will take a month.