jacobus, i think you are perhaps wrong.
i had some goats for a short time earlier this year with very dodgey tagging arangements when they arrived. all had the same flcok number tagged in their ears, but 5 or 6 of them were not born on that holding- innocorrectly tagged by a government agency!
from defra's guidance i worked out that before the goats left my holding they had to have S-tags, which are just a tag with S-(uk flock number) and are really easy and cheap to order/buy from farm suppliers (i had thought buying such a small number might cause problems).
defra said:
"All sheep and goats must have a Defra-approved eartag applied in one ear with a unique numeric identification number, which must start with UK, followed by the 6-digit flock/herdmark of the holding of birth, followed by a unique number for the animal (up to 6 digits). The tag must be fitted within 9 months of birth if the animal is regularly housed outside or, if not, within 6 months and, in any event, before the animal leaves the birth holding. The tag must be visible from a distance and can be any colour, except red.
Before an animal leaves any holding it should have a tag with the flock or herd mark of that holding. Animals can therefore leave their birth holding with their holding of birth tag. However, if the animal is to move again the keeper must apply a movement tag which bears the letter S followed by the flock/herd mark of the holding it is about to leave. The movement tag will not have an individual animal number. The same applies to the next move the animal makes – a further movement tag should be applied. However, once an animal has three official tags, further tags cannot be applied for welfare reasons. To make further movements, the keeper must then record the full individual identification number of the animal in his holding register and in the movement document. If the keeper does not wish to apply an "S" tag for an earlier movement, they can instead record the animal’s full number in the holding register and the movement document."
so farmers_wife: i think you need to order some s-tags using your flock number when it arrives, but the tags need'nt be applied until they leave your holding, but its probavbly better to just do away with it and get it done now.