Not sure if this will be an issue or not ... but this year, the second year of compulsory EID sheep tags, the Shearwell applicator had to have an adjustment made. If you had last year's applicator you got sent a different pair of jaws to put in them for this year's tags.
2010 tags won't work with 2011 applicator jaws, and vice versa.
Just in case you have a problem and can't see why, I thought I'd mention it.
Cheers
Sally x