Sorry I can not be of more help vnice as I am not starting my new job until this Monday.
After that, no problem in giving you a source, so maybe for next year's truffle season!
What I would suggest is, IIRC you said that you had purchased from Urbani in the past? I would contact them and see if they could recommend a source here in the UK. They may even buy their truffles via a broker here in the UK or use someone as a freight forwarder.
Below, I have listed the name of a company I used for French and British items while I worked at Universal in Orlando. The have offices in Pitlochry and Tomintoul and the owners name is Dave McPherson. I think they could be your best bet. I had some frustrations with them while at Universal as far as meeting deadlines. In saying that, when you are dealing with international shipments of Fresh fruits and vegetables, it is such a headache and then dealing with the USDA! I would call them at the very least and see what they have to say. Maybe they can not supply you but they can point you in a better direction than I can at the present time. They have a very cool item that stands out in my mind, Baby dried morel mushrooms about an inch in height. They were from Tibet and they cost $200.00 per pound. Just in case you are interested!
McPhersons
Telephone and fax
Tel: (01796) 472305
Fax: (01796) 473480
Address
Brook Place
60-62 Athell Road
Pitlochry
Perthshire
PH16 5BL