I've been here nearly 6months not having to worry about border runs, I dont want to start that. After this visa finishes I'll either look at alternative visa type or return to UK for 6months.
Firstly get TM30 from hotel, go to immigration and get certificate of residence if they say 2weeks ask for express service pay extra, go to hospital get a medical takes about 30min, go to DLT early in the morning and should get it sorted same day. You'll get 2 licences, car and bike.
If you've brought your UK driving licence it should be a simple process to get the 2yr temporary driving licence. There's plenty of websites explaining the process, medical 100baht, certificate of residence, and allow for a day at the Department for Land and Transport. No need to use an agent.