A Prisoner of Privilege is the 18th and most recent (2019) in Rosemary Rowe's Libertus series, set in Roman Britain. It has dropped to £1.27 at Kindle UK. I really like this series, and so I'm happy to see this most recent title on sale at good price. This is one that I hit the "buy" button on before I even did the post, so as not to miss it!
And, if you want to try the series in order, the first nine titles are published by Headline and have been long-term (at least the last couple of years) at $3.99/£3.99 in the US/UK, which is not totally awesome, but is still pretty reasonable. Sadly, the later titles are published by Severn House and are mostly $10 and up (!!!) in the US, and £5.79 and up in the UK - sigh! Which is why it's extra-nice to see the most recent one on sale...
Kindle UK:
https://www.amazon.co.uk/Prisoner-Pr...dp/B07TVF168K/
Kindle UK/Smile:
https://smile.amazon.co.uk/Prisoner-...dp/B07TVF168K/