Historical errors -- a slight rant

I love history. I also love historical romance. I fully accept that when I read historical romance that it will not have happened. But I do like to think -- it would have possible. Or is at least has some modicum of grounding in real life.
But it does bother me when the author's historical note afterwards is wrong. I picked up the latest M&B Super historical by K Micheals. A Regency about Queen Caroline. She went on about how not that much was known about Queen Caroline. Slight news to me as I can remember reading an excellent Jean Plaidy as several non fiction books about George IV's erstwhile consort. I became interested in the era after reading The Young Victoria. I wanted to know more about Princess charlotte and Prince Leopold. Leopold was one of Victoria's main adviser's. There is a wealth of material on the era...if you know where to look. The reason Queen Victoria was born at all has to do with the unfortunate death of Princess Charlotte.who died in childbirth in 1817.
But I really raised my eyebrows when she stated that Queen Victoria succeeeded George IV. Umm, what about William IV and Queen Adelaide?
The offending passage by Kasey Micheals in her author's note states King George IV...never did remarry so that upon his death, Victoria...became queen.
George IV died in 1830 and his brother William succeeded to the throne. Wiliam IV died in 1837 without legimate heir when Victoria became queen much to the disgruntlement of George and William's younger brother who became Elector of Hanover (as Hanover had a bar on women succeeeding)
William IV was the last British king or queen to freely chose his prime minister. How can anyone ignore 7 years of rule?
Those seven years meant that Victoria was able to rule on her own rather than having to suffer a regency with her mother, the Duchess of Kent holding sway.
To say that Victoria was George IV's heir was wrong. Sailor Billy was.
A small point to be sure but if the woman had spent 25 years writing about the regency era, surely she should at least know her kings and queens of Britain.
Call me unreasonable, but I do like the framework of history to be correct. Play what ifs BUT get the dates right, the kings, queens and presidents in the correct order, as well as the battles. Otherwise, it makes me want to throw the book across the room and more importantly makes me resovle NEVER to read said author again.