Overseas delivery of jewellery from the UK

Hi all I have another question - this time about delivery. I have an
increasing number of overseas customers but am having trouble finding
a company who will track and best of all insure jewellery in transit
for a reasonable cost. The Royal Mail are quite good inland and for
some countries but will not insure jewellery sent to the US because
they say there is a lot of postal crime in the states. The only
companies I can find will only track for about �30 per go - even if
the item is only worth about �50. Does anyone know of any good
companies to try for this? Thanks and best wishes

Harriet, Hitchin, UK