They very very occassionally turn up on ebay - but not seen any for a while .
Why not contact Orange direct - the badges still appear on new bikes so they must have some spare ?
from support faqs
Can I order replacement stickers for my Orange?X
We offer replacement stickers for most models. We may not be able to match your original decals exactly, but suitable alternatives will be offered. All kits include a full set of decals and a metal head-badge.
To order sticker-sets give us a call and be prepared with your frame number and colour so we can find a suitable match. Standard kits cost £19.99 including UK postage.