
Hi Charles.
I have Borders too. There is no height standard for Borders just weight. There are NOT many Borders that are the ideal weight. I see so many Borders too thin because people try to keep down to the standard as much as possible. These dogs look ill !!! The Border Terrier should be capeable of being spanned behind the shoulder (I am sure you know what that means) so if you can do that, then chances are you dog isn't too big, but thats not to say they are not overweight. I doubt your dogs would be too fat though if you work them, mine all work, and I would say that during the summer they tend to gain weight more easily, but as for getting fat, no.
My best worker and show dog weighed 17.5lbs, he was rock hard, not an ounce of fat on him, he was spannable, so "theoretically" too heavy, but the most versatile, capable Border I have met, he did the work of a Spaniel, Retriever and a Terrier!! I am sure I could have got him lighter but to what end, a rosette, a place in the line up? not a chance, FIT NOT THIN, thats what I say. Good luck with your Borders Charles, and happy hunting !!
Dawn.