I believe you can only use replica tags on stock you’ve breed yourself...with bought in stock one must use replacement red tags.- not sure Re Scotland.
That is not what I have been told by Shearwell. Based in England.
I looked it up because it certainly used to be the case that you couldn't get replica tags for other than homebred sheep. But clearly the rules have changed and all the vendors offer this now.
It also used to be the case that an animal with red tags could not be sold on again or exported, but that seems also to have changed.
In your case, Maysie, because of the pedigree registrations, I would go for replica.
Plus, there may be a residual antipathy to red tags because of the (now outdated) rules restricting onward sales. So if these animals could be sold on again then I would definitely go for replica.
When you talk again to Shearwell, ask if these specific tags have free lifetime replacements. Depending on how the original owner bought them, they may do
3 sheep losing Shearwell tags suggests a problem with applying them, to me. Shearwell change (improve) the applicator jaws from time to time, and using the wrong set with specific tags can result in them not snapping shut properly. A breeder should know where and how to apply tags to reduce losses, so it is unlikely to be positioning, I would hope.