Did everyone recieve a DEFRA booklet which outlined the new EID rules??? You are allowed to remove tags on welfare ground, however these have to be replaced once the ear(s) have healed. Also if you are having problems with only the tag with the EID tag in due to the extra size / weight etc it may be worth considering a ruminal bolus. These, are inserted down the throat and sit in the bottom of the rumen. When scanned they contain the same information as an EID tag, you then have 2 normal tags in the ears which have the number which can be read visually. I have also found in my experience that tag losses are usually connected with one of a few things: Using incorrect pliers to apply the tag / incorrect placing of the tag in the ear / poor tag design (ie choosing the wrong shape or type of tag for the breed & management systems use etc) It will most defanitly be a game of trial and error until you find the tags that are best for your flock.
A useful piece of info....lambs do not have to be tagged until they are 9 months old (if kept extensivly) 6 months old (kept intensivly) or before they leave the holding. It may be worth only applying the non EID tag whilst they are home (for management purposes) then before they go or when they get to the stated ages then apply the EID tag.....the lambs ears are likely to be bigger then and the tag will not be so disproportionate to the size.
However I think as much as the EID regulations seem farcical and pointless, as a British Producer one of our key selling points is that our meat is fully traceable.....in order to make that claim we need to make sure it is!