I am a big fan of bitters, and British Ales in general.
Brew Enhancer? Is that dry extract? I hope that is not sugar. Not that sugar in an English ale is bad or even out of style. But that is A LOT, especially in conjunction with the molasses.
Counting that it is extract, it looks like you have the bases for a decent simple best bitter. Molasses can easily be overdone, but being in the kit they likely have it dialed in. And that amount is on par with a good amount in 5 gallons. What is the yeast and hops? They will make it a bitter as much as, actually more so, then the fermentables profile.
Keep the carbonation low and serve cool, not cold, to be "authentic".
"There's many a slip twixt cup and lip" -idiom