I find the concept of ordering meat online to be so alien! I hope your new butcher gets some in at some point though.
Btw, I think I have seen tripe and ox kidneys for sale recently, I think in one of the groceries in Chinatown when I last went there in the last 6 months or so. I live near a few Asian/Turkish butchers/grocers and they are actually pretty good for stocking a few things which are often overlooked by other butchers.
Some people (like myself) have issues with B12 deficiency, offal (eg liver and kidneys) contains huge amounts of it, it really is great for you and can be incredibly delicious if given the right attention, a shame it's often overlooked by many.