unfortunately i also have to agree with issybird. i tried to start a few of the austin continuations, but she's expressed perfectly what i thought about them.
frederica is a great georgette heyer to start with. it certainly was for me years ago - it got me hooked. i love many of her regencies/historicals, two of which - Cotillion and A Civil Contract break some of the regency traditions. and her first book, the black moth, can be downloaded right here on mobile read. it's actually another of my faves.
mobi
https://www.mobileread.com/forums/sho...ighlight=Heyer
epub
https://www.mobileread.com/forums/sho...ighlight=Heyer