I think you need to use Special Delivery and cancel Ebay label.
In my opinion that is the only way to ensure you are protected.
If lost/damaged etc. while buyer would be protected I am sure it would be at your expense.
Ebay do not seem to understand their own restrictions,
- Valuables, such as jewellery, watches, and precious metals, including, but not limited to, jewels, watches, gems, precious metals, real pearls, silver, gold
