Update on this: ive heard that it will get through if the seller does not include things like “mercury vapor” or “HID” in the item description. You need to contact the seller after making a purchase and getting them to write something like “vintage antique light bulb” instead.
The problem is with any listing containing the title or description of the item as a "mercury lamp", "mercury vapor lamp" etc.
Liquid mercury has never been allowed to be transported on planes as it is reacts with aluminium (which the plane is partially constructed with).
I think it is pretty unlikely that the Goverment is specifically banning the export of MV lamps. It is more likely that there may have been a recent incident with an item found to contain mercury in a parcel that has made the customs focus more firmly on items listed as containing this metal.
For all of the many international trades I have done with lots of collectors in different countries around the world, I always list the item as "light bulb" on the customs form and have never had a problem.
I don't even put "vintage or antique" because this could indicate a potential higher value of the item which could attract fees or possible theft.
If this rule is followed, collectors should have no problems exchanging lamps with each other internationally.
The trouble with the lamps on eBay is that the seller's description is what is fed into the Global Shipping Program and will show up on the customs declaration.
For this to be avoided, the seller either needs to:
1. Ship the item directly to the seller at the post office with "light bulb" on the customs form.
or
2. List the item on ebay with a title and description that contains no mention of "mercury" "discharge" "HID" etc.
They could just list the item as HR400A33 bulb, H39KC-175/DX lamp, 400W MBF/U lamp, 125W HQL bulb etc.