Are you talking about mailing eggs?
I know in the US, most states dont recuire anything special. Eggs are usually sent express or priority (2-4 days). Maybe you could call your local PO and ask, hopefully someone from the UK will see this and answer for you.
Eggs may be sent only by Priority Mail International. See 550 for nonpostal regulations on dried whole eggs.
Eggs must be packaged in the following manner:
Eggs mailed to any country except Canada must be placed in a metal egg container. Eachegg must be packed in cushioning material. The metal egg container must be enclosed in an outer container of wood with cushioning packed between the two containers.
Eggs mailed to Canada may be packed either as prescribed in 138.32a or in a box of rigid material with a tight–fitting lid. Each egg must be wrapped in protective material and placed on end. Vacant spaces in the box must be filled with packing material to prevent the eggs from striking each other or the box
So inbox your address I'll send you 6/12 eggs just to try it.
Worst they can do I guess is bin them .? Not sure on that
If you could do the same