Good question, I wasn‘t aware that you‘re not insured outside Thailand with such a first class insurance, normally you are insured as well with such insurances. I‘ll have to check with Roojai as we also intend to drive outside Thailand like so many other drivers
What was the reason of rejection from the bank? Normally if you have a non-immi O based on retirement with a proof of rent or house in longterm contract + Thai mobile no. there shouldn‘t be any problem to open a bank account.