I don't expect historical accuracy from romance novels, i read some for they predictability and hopefully a few laughter,great combo at the end of the day.
However i do expect a general knowledge that give the feeling of the period.
Her heroines are too modern,she doesn't seem to have a clue about regency fashion. In this book she attributed the "Mona Lisa" to Michelangelo,and she seem to have placed the statue of David (which was sculpted by Michelangelo) in Rome.
Maybe I'm too demanding,but really if you have no knowledge of a subject don't put it in your book without researching it first,especially if is something so banal that can be found on Wikipedia.
Also enough with the "hessian boots" you would think that for a whole century men didn't wear anything else.They are quite silly looking by the way.