Unfortunately labstuff seems to be a dead site, there has been a notice on that site for months now that they don't take any new orders because they are too busy. And the other one doesn't carry Ammonium Dichromate. Concerning people who do pyrotechnics, I don't know any. As for now I have found a company in the Netherlands who should deliver to private persons and to Belgium but their shippingfees are quite high but I took the gamble to order 500gr. Still out however for a more domestic source.