Hi Lee, I wouldn't be giving him lamb shanks either. Too small, he could choke and the bones can splinter. You are far better off sticking to the brisket bones and raw chicken wings. Why not a big marrow bone cut in half for him to knaw on?
You will find that all vets will tell you something different. Often best to stick with breeder's advice. My dogs have near perfect teeth. Just a tiny bit of tartar.
The first time I took Leo to the vet I was told never to let him go swimming cos of the deep ear canals, and that I should feed him tinned Pal!
Two bits of advice I have never heeded.
Do some research on BARF diet and the additives, and have a look at
http://www.greenpet.com.au for supplements and dental products.
Watch out for the European wasps that are around at the moment as well. They love the bones too!