Is it okay to send cash or must I only send a postal order. It mentions to pay via postal order on their site and says you cannot pay by cheque. They do not mention anything about cash,  I have used cash in the past but want to make sure before I send anything off.
 

You could send cash but it would be at your own risk of it not being accepted or lost along the way.

When you apply in person at the London Embassy, it is cash or postal orders only.

As your sending your passport anyway, stick the cash in and send it Registered mail next day delivery.

Allow at least 10 working day's though for the visa although you tend to get it quicker at quieter times of the year.

I believe you need to allow enough money for the return postage if you need it registered signed for.

If your closer to London, it's easy to drop it in one day and collect the next. Check the times though as it's a short time window.

I would have thought it was fairly clear.

 

" Visa and postage fee must be paid by Postal Order made payable to: THE ROYAL THAI EMBASSY.please kindly write down the applicant 's name and passport number at the back of the postal order  "

http://www.thaiembassyuk.org.uk/?q=node/401

 

"  - Each applicant must enclose self address envelope and pay an extra £10  on top of the visa fee to cover the return of passport "

There you go Postal Orders only by post......and don't forget to send a copy of your travel documents.