Yeh, my lot gave the NM raw the thumbs down! yet they will eat any raw meat normally.
Was it bonemeal you mixed with his meat Mel? Must admit I'm surprised he didnt take to that, mine will try and stick their noses in the tub of bonemeal! and they love it mixed in with meat - in fact somedays when I'm not feeding raw and they're looking at their canned/pouch offering with distaste - if I sprinkle a bit of bonemeal on the top - thats it, heads down and they finish the lot LOL!
- but what I'd do if he didnt like it being added, just give him his meat without anything in, then next time, add tiniest amount of bonemeal and gradually increase the amount - as you don't need much anyway. Another good trick is pour a little of homemade stock from the roast dinner on Sunday over his meat.
You could try a different form of calcium in his meat, like ground up eggshells (which is calcium carbonate) or you can just buy calcium carbonate - pretty much tasteless. You could also try a supplement called Instincts - and again I'd do the same, and not add the full amount first off and gradually increase it. Adding Instincts makes it a completely balanced meal. You can get it here
http://www.realpetfood.co.uk/Having said all that, unless you are going to feed ONLY raw, then its not really so important to make sure each raw meat meal is a completely balanced one - because if your'e feeding other 'complete' foods then he will be getting a balanced diet anyway.