This occurred to me. As tea lights already come in a metal case I’m not sure why additional precautions are required. I suppose thought that some tea light casings could be very thin and likely to not offer much protection?
Safer all round I suppose to use a glass or more robust metal receptacle for them.
I did experiment with a Brass 1" candle insert in a pine candle stick allowing it to burn down into the insert.
Test 1 was with a soy dinner candle that had a pool of molten wax that extinguished the flame when the candle wick got below the top of the holder, all good wood was warm to the touch but no charring and no fire.
Test 2 was a paraffin wax candle that stayed alight down at the level of the holder long enough to cause the wood to blacken and eventually catch fire.
Obvious really that flame heat and wood are not a great combo to be left unattended in the house (my test was in the middle of a cleared concrete floor of my workshop, and I was watching it)
Certainly both candles were perfectly safe if extinguished before they reached the holder, and the standard warning signs for candles should cover this. BUT a tea light that is in a drilled hole in a flammable material made from a high heat wax is not in sufficient insulation to prevent it scorching and possibly igniting the holder. I mostly don't make candle holders any more but if I do I prefer a metal dish with a spike to fit the candle, or a glass liner for tea lights.
5 volt LED's are a much better option for makers in my opinion.
The original question does raise another thought though. As a maker I can make table lamps and sell them at a craft fair type place (in the UK) without certification or PAT testing them (sure that should be PA testing!) as long as I only sell 4, once I put 5 on sale the rules change. The opening question was about a shop not a maker selling items and that may change the labelling and other requirements, probably worth a direct question from the shop to trading standards for specific advice.
