Kev, this is a really catchy tune, and I think you did a great job on it. The vocals sounded fine, in fact, better than fine

. The whole thing came together really nicely. You had such a good groove going, I'm not sure I would have stopped for the 2 a capella breaks, but that could be a personal taste thing.
Maybe I'm nuts, 'cause no one else mentioned it, but I was thinking I heard some tonal conflict with that underlying guitar melody line, like maybe a string was out or something. Ignore if no one else picks up on it.
Overall: catchy, different and really original feeling tune... one to be proud of for sure.