I used to feed my GSD James Wellbeloved, he has a sensitive stomach and it was great for him and he loved it, but I was the same as you garry it cost too much, he was eating more than a bag a month.
My uncle who has gun dogs suggested skinners which costs around £15 for a 15kg bag and he's had no probs with it, been on it a year or so now and never had the runs once - can't be bad .
Also it calmed him down a smidgen as it's lower in protein, which I understand can contribute to hyperactiveness - and he's a nutter