The Royal Mail have now changed the restrictions on posting water-based paints to the following:
If, like me, you think this is patently ridiculous, there's a petition here you can sign.Water-based paints, wood varnishes and enamelsThe items must be securely closed and placed in a leak-proof liner, such as a sealed polythene bag, so that any inadvertent leakage is contained within the outer packaging. Surround with absorbent material such as newspaper and sufficient cushioning material to protect each item from damage. Volume per item should not exceed 150ml. No more than four items can be sent in any one package. The sender’s name and return address must be clearly visible on the outer packaging.