Well thanks for your input guys. I've probably owned 25 longbows and I have never had this problem with any of them. I want to like this longbow but I don't think I do. I can take any of my other longbows and shoot them well.
You give up too soon. I can't imagine a Sparrowhawk that's difficult to shoot well, they are Very forgiving longbows for both arrow selection and shooting form.
Noting that your problem is a consistent grouping of arrows off their intended mark tells me it sure ain't the bow, it's the shooter and/or arrows.
Sparrowhawk limbs are intentionally narrower, and thicker with their added tempered bamboo limb core, and thus are quite forgiving for bow torque. They are +1/8th inch of center shot, so as with any true longbow there will be some issue of arrow spine, so make sure to try different spine arrows. My 'hawks in the mid 50s @ 29" loved weak spine Beman 500 shafts that were low 4 fletched.
Other than that, it'll be a form issue anomaly to uncover and conquer, and first to look at is yer bow hand, it's pressure point on the bow's grip, and what happens during release. If you rotate the bow hand from near vertical to perhaps a cant of the hand (not the bow) to about 45*, with the pressure point at the thumb base, that will be as torque free as it gets. Then it's up to arrow spine.
One key with all stickbows is how the shelf/window is cut. The more it is cut to center, or past center, the less arrow spine matters. There is typically a good difference 'tween a +1/8" arrow plate and one that's cut way past center. I have a hybrid mild r/d longbow that's 1/4" past center shot and the plate is faced with 1/32" thin leather - that bow shots dead straight with any spine wood or carbon arrow as long as my bow hand is properly placed and the rest of my shot form is well on ... doesn't matter if the bow is "target archery vertical" or "bowhunter severely canted". The accuracy is then up to the bowsight between my ears and how it elevates the bow arm, and how the string fingers do their releasing thingy.
In any event, giving up and selling off yer Mohawk shouldn't be a problem since Vince has "retired" from bow building for the most part, and Sparrowhawks are hard to come by.
Good luck.