I think Callum's a good prospect, I've seen him spar and know a few people who have sparred with him, the kid has legit power plus he has a great frame for when he eventually moves up in weight.
How far can he go? That's a totally different question to answer. He is definitely going to get some honours at the British and European levels, which is a great achievement in itself. Can he be world class? I'm not sure. His chin will have to be tested and his stamina in the later rounds against tough, strong, championship material fighters. I hope he does good!