There are some pretty wild differences between English and American traditions - I would tentatively say that the English style is very much more polished and 'finished', and possibly somewhat less 'robust and workman like' than the American style, but there again the American leather carving work is painstaking and incredible, and the English have really no history of that sort of work at all - if we get all crazy and decorative we might make a bridle noseband and browband with a raised, swelled effect, or a little pattern of decorative stitching, but no more (particularly for strictly riding horses - there is a tradition of decorating harness, even relatively work-a-day harness, but its mainly brass decorations rather than carving).
There does, here certainly, seem to be a link between the 'class' if you will of the user/animal involved and the amount of decoration.. For example, you might see quite a lot of decoration on the harnesses of horses towing narrow boats, or a brewery dray.. but an upper class ladies hack would have very plain and strictly BROWN tack (black was for harness/work animals), though finely cut and stitched incredibly finely (the finest I work is 12 to the inch but apparently 16 to the inch was popular 100 years ago!).
Anyway.. I digress, heres (if i can add a picture) an example of my sewing using the double handed techinque: