Secret Danger is #143 in Barbara Cartland's Pink Collection and was published in August 2016. Belinda Lanwick is in mourning for her father when she first sees Lord Ian Cheddington. When she hears about a plot against him, she goes undercover as a lady's maid in order to save him.
This cover is identical to the Jove edition of In the Arms of Love. Unfortunately, I don't have a photo of the original cover art.