In the short story The Case of the Perfect Maid, Janet is the maid of Mrs Carmichael, one of the tenants of Old Hall. Lavinia Skinner says that Janet is "a fixture" but tends to "bully" her employer. In Lavinia's opinion, Janet is "the most disagreeable woman", but she doesn't give any details.
In the NHK anime adaptation The Perfect Maid, Janet appears as the maid of Mrs Carmichael. Her employer Mrs Carmichael tells Miss Marple that while Janet had many faults, good help was hard to find. Later, Mrs Carmichael is chatting with neighbours and they observe Janet slacking off. She remarks on the same theme that one had to accept such things. Janet has no lines in this adaptation.