I e mailed London few days ago asking same question they said multi entry non O not available and sent me details of metv and OA as only multi entry visa,s available
as Diane says above O A visa gets you nearly 2 years stay paperwork is really quite easy I just did it and no need for money in Thai bank account. go thro list tick off boxes and post to London, was back 5 days later. Agent will charge lot of money for nothing