So did I went to my local immigration they gave another one and updated their records free of charge,JUST Get IT SORTED ASAP some people say you need to report loss at police station,I didn't but guess its depends on each area worst case immigration will tell you to report it
I THINK I had to show 10k in UK bank account for previous 12 months to be granted the non o visa, I think you can come on visa exemption and apply for non o visa in Thailand BUT you will probably need to have a return ticket ,flying in on non o visa I did not need return ticket
If your more than a few days over PREY you get to the airport it's not too bad max fine 20k bht if you stopped before I've heard your looking at being blacklisted for up to 10years