The assay stamp is really for consumer protection, to prove that what they are buying is in fact a precious metal, the makers mark is to show which silversmith created it which is great for the one off peices created by PMC. I know the Birmingham assay office do a 24 hour service (it costs a bit though) The acual makers stamps cost £60 and you will need 2, cranked and straight, if you make rings as well. You have to pay £47 to register, then the £120 for the two stamps and then between 16p & 50p per peice for hallmarking depending on the size of the item. They do have minimum requirements so you are best off saving all your assaying until you can send it all at once. Hope this helped :)

Okay, I have a hallmarking question or two... If your own personal hallmark stamp is not legal, why even buy a stamp to stamp your piece (stuff over 7.88 g meant for sale)? Also, how does the assay office work? Presumably you send your piece to them, but how long do they keep it on average? I want to make custom orders and I'm wondering how to fit in the hallmarking.