I have health insurance, personal accident insurance, and comprehensive motor insurance.

I'm looking for a simple no frills Life Assurance policy. Paid monthly that will leave perhaps 1-2m baht to my chosen next of kin (non-Thai).

Me: Male in my mid 30's.

Any policies that you know of?

It sounds like you mean life insurance - a policy that pays out a lump sum if you die during the term. All insurance companies offer term insurance plans. You need to contact an insurance broker, I used Chaz in Bangkok as they speak English and my Thai isn't up to much. They'll listen to your requirements (term and sum insured) and provide you with a range of options from different insurance companies.
For example, Thai Life Insurance, Koomsub Non-Dividend term insurance plan, 19 year term, annual premium 9,900baht, sum insured 1,000,000baht etc.
If I've misunderstood and you do actually want life assurance - a mix of investment and insurance - you need to contact an independent financial adviser. A company such as Infinity will send an adviser to meet with you and discuss your requirements.