I’m sure it will be fine , most are glad to have tenants anyway , so it would really be in their interest to be too rigid , especially under your explained circumstances ..
For a few weeks ? And you pay monthly direct to your landlord, and not via an estate agent ? .. you can just set it up to transfer to either , or as it’s only a few weeks maybe just ask them that you’re be a couple weeks late .. as long as you pay within the month I’m sure it won’t be an issue ?
You will be fined 500 bhat per day for overstay .. it’s no problem and no issue , unfortunately years ago I did it many times , 2-3 , and a couple of times 5 days … infact once they told me I’d overstayed by 2 days , and never even fined me ! .. that all was years ago , but my understanding ( I live here now ) is that they are quite happy , as long as your not taking the pi** ..
There’s a Bangkok Bank in London which I’ve dealt with before , ask them .. but I must admit I’ve never used my cards , so no help there I’m afraid .