An Assassination on the Agenda by T E Kinsey is £0.99 at Amazon UK today.
https://www.amazon.co.uk/dp/B0CLVRB9JQ
This is the 11th and latest of his Lady Hardcastle mysteries, first published in May this year.
July 1912. Lady Hardcastle and her tenacious lady’s maid, Florence Armstrong, are enjoying a convivial gathering at the home of their dear friends, the Farley-Strouds. The only fly in the idyllic ointment seems to be the lack of musical entertainment for the forthcoming summer party—until, that is, Lady Hardcastle’s brother Harry calls with news of a murder.