I have just had a conversation with the Thai Consulate in Hull here in the UK. I have applied for a Non O visa multi entry and it seems to have taken some time to come through. They had told me now for the Non Immigrant O visa, either single or multi entry, you have to show proof of why you wish to be in Thailand for a long period of time and that proof is then sent to the London Embassy for approval which can take an extra few days. This has changed slightly as i used to post the application off on a Monday and get the passport with visa back by Wednesday. They are now advising 5 working days