I would ask for a receipt for your chemicals with each individual chemical listed AND the weights that they siezed being listed too. (That means the buggers will have to weigh them if they haven't already, which they won't like). Also ask them to produce copies of the relevent legislation including highlighted paragraphs that they used to sieze them under.
Do they know what they siezed? Just because the container has a chemical name on it, it doesn't mean that's what's in it. Ask them to confirm by chemical testing that they have siezed what they say they have (Police budgets are stretched as it is, they won't be keen on paying out for expensive chemical tests on each individual item.) If they refuse, they can't PROVE that they have what they say they have.
If they can't do this, simply ask for them back as they have been illegally siezed. If they can't show you what you have done wrong in writing, they have no case.
Further more confirm that they are still being stored and have not been destroyed. If they have been destroyed, they have destroyed evidence, if they haven't, they must be stored appropriately per regulations.
Tell them that you want them back so do not dispose of them.
Take legal advice, try Citizens advice first.
Maybe someone on here can help you by videoing putting a flame to these various chemicals to demonstrate that they do NOT explode in contact with heat and offer to do the same for them as a live demonstration with a little of your chemicals.
Lastly GOOD LUCK
Edited by Mortartube, 30 July 2011 - 11:48 PM.