Good questions:

Dalewood: Rental costs probably vary but go to the same place and I pay 150 baht per day and as there are so many places hiring out you should be able to negotiate that rate anywhere. Insurance is best done from your own country and each policy will differ regarding theft or accident.

Scottish: Legally you need an International Driving Permit and in the case of The UK they are issued by The RAC and The AA. But unless your UK driving license specifically allows you to ride a motorbike it will not have the stamp and so will not give you the permission to ride a motorbike in Thailand. However foreigners riding a motorbike without the correct license in Thailand is a good source of income for the police and is therefore no big deal. If stopped you will be issued a ticket and this involves a 500 baht fine. It is still worth having the permit because the police will keep this and allow you to ride off. It is best to pay the fine at the police station because you get a receipt and you can show this the next time you are stopped and will be waived on. Your license is returned once the fine has been paid. Over my recent 10 day visit I passed many police checkpoints but for some reason was not stopped once.