Hello Shropshire lass you can't be very far away from us as we are in Clun country too, we keep Zwartbles though at 1000ft, and have also starting with a few Shropshires this year.
You will need a holding register and to decide whether your flock are grazed on the same holding as your family farm or whether you have your own holding number. You can have several seperate parcels of land under the same holding number if they are not too far apart (I think 5 miles but would need to check) so then you wouldn't have restrictions moving animals between fields etc.
re tagging breeding tags will be double tags with an individual visable number, slaughter tags can be eid or non eid (if non eid they can't be upgraded to breeding tags if the animals are sold) these will just have your holding number on, although are also allocated numbers by Defra apparently when issued, they are ok to use for up to one year old in slaughter animals. For pedigree stock you will probably also have management/pedigree information to include on the tag.
The Animal health officer at Shropshire Trading standards is very helpful, unfortunately I can't remember his name, if you want any advice.