When Alexis Hall describes his book as "a big gay regency romp about a overly dramatic beautiful rainbow sunshine unicorn + a overly dramatic demisexual grumpy duke, going on a cross-country chase" and adds that the unofficial subtitle is "Dude, Where's My Curricle?" and it's the "campiest and silliest and most fun thing" he's ever written — believe him. 

The grumpy/sunshine combo is gold. I disagree with reviewers who felt Bonny Mr. Sunshine was overly mean to His Grace Valentine Grumpy Pants, but he was certainly in an unenviable position between his best friend and sister, His Grace, and his own, you know, precarious existence. And while a zero to 100 relationship for a demisexual main character doesn't quite work for me, I also disagree that His Grace was "just fine the way he was, oh em gee, just leave him alone already." He was not quietly content — he was miserably unaware and misguided and headed for further misery. Most of the side characters are great, though the satirized gothic heroine sister is just grating. And the plot is, well, a careening mess that's somewhat too driven by the bullying sexism of the day, anachronistic overcorrections, and aro understandings clashing with gothic dramatics, but mostly it's just a vehicle for fun shenanigans in the countryside. It's all undeniably over the top, British, queer, chaotic, funny, annoying, graphic, and sometimes genuinely touching and lovely.