M Smith, I've never dealt with Bolks, but dot your 'i' and cross your 't'- the Dutch are not to be trusted.
Mr. Chambers, I'd advise all due caution in business dealings in Russia. It sounds extraordinary, but I'd insist on my funds being held in an attorneys' (yours or perhaps one in UK) escrow account pending receipt and verification of all government releases. You may have a right and standing to bring suit, however laws governing business and/or commercial transactions are still evolving, especially those aspects regarding 'default,' e.g. it helps to be French (Russian) when you're in a French (Russian) court-everyone else is just a stranger, so to speak. In alternative, you can go to Russia. Traveling to Russia isn't much of a problem. You'll need a visa to enter the country, of course and yet another one for the hotel you'll be staying at. At some point, probably at the hotel, you can expect ALL of your papers; USA passport, visas, plane tickets, hotel receipts, etc. to be confiscated so that you can be 'checked out' by the local authorities, which makes you 'invisible'- non-existent - a 'non-person' so to speak. America and Americans, in turn, as you can imagine, aren't at the top of the popularity charts in Russia, these days. I think that we've been flooding the international poultry markets with our chickens and hurting their domestic chicken growers. As an aside, the Russian government, as regards art and antiquities has been rather aggressive in claiming property, held in other countries, as being their 'national heritage,' and seeking, by demand, its return. Others mileage may vary. My experience and information is about a month old. I wish you all the best in your negotiation and acquisition. So, Mr. Chambers... do you mind it I call you Jim?... What is an American imperialist gun-runner and antiquities forger REALLY doing in Russia? Your embassy? Our records show that you haven't checked into you hotel yet. Just KIDDING! But, please be careful whether you do this at arms-length or in person.