The Masqueraders by Georgette Heyer

Easterly Woods lay but two miles, across country, from my Lady Lowestoft's house, and John covered the distance swiftly. He came to the house by the river as the lamps were lit, and found my lady waiting in the hall, and Sir Anthony's chaise in the drive outside. He pulled off his hat and spoke before my lady could open her mouth. "I took Mr. Merriot's message to Sir Anthony, my lady," he said in a voice loud enough to carry to the listening lackeys by the door.

My lady's black eyes snapped. "Yes? " she said. "And he said?"