Your butcher only pays £3.00 per KG for on the bone brisket which are about 16KG in gross weight, about the same price. Offer him £4.00 KG and cut and trim yourself. Mine does it for £65.00 to £70,00 cut and trimmed as it only takes him 10 minutes
It wasn't huge I would say the waste was about 2.5 to 3 KG mainly the curved bone from the breast plate making it net about £4.90 per KG. I have pictures of the whole piece and how it was trimmed but its a ball ache to post them on here (You can see them on Smoking Meat Forums @ "North East Butcher Convert"). Needless to say I got a piece of brisket that was 8.6 KG plus a good large rack of beef plate ribs and some "African ribs" (as a butcher my way calls them) so 3 cuts for my money. I also got to see what I was buying and see it trimmed. The fat waste was quite small only about 750gms. However you can see why other online butchers charge what they do as the loss to the Plate and Ribs (go in beef sausage) means they have to charge more to make up for the loss. So just go big for better value