@Jay *******
i really don't know about the UK . If you need a police clearance follow this process and oh btw I didn't know it cant be emailed to you but posted instead.
So don't leave it to the last moment but follow this process
"Application Process (For applicants residing abroad) 1. Complete the Application Form, Testimony Memorandum Form and Fingerprints Form2. Complete the Supporting Documents and Self-addressed envelope3. Pay the Processing Fee 4. Post (1 & 2) directly to the Police Clearance Service CenterRoyal Thai Police, Building 6, Rama 1 Road, Pathumwan, Bangkok
*****
Thailand5. The process will take 15 -25working days if all documents are in order.*Delays may occur if acriminal record is found or if all of the required documents have not been submitted6. You will receive your Police Clearance Certificate by post*Please note that you may submit your application by post to Royal Thai Policeor/ you may ask someone in Thailand to submit the application on your behalf"