Any Agatha Christie fans about to help me remember a book title?

[Psychicpineapple]

I have a feeling it isn't a Marple/Poirot but I could be mistaken. There's a young woman who goes undercover as a maid, a rich American and a famous lawyer I think. I've googled to no avail. Any ideas?

Is it a Tommy and Tuppence one?

Possibly. I had forgotten those. I'll have a look at them. Thanks

Could it be The Secret Adversary?

At Bertram’s Hotel?

The 450 From Paddington?

Oooh I am a Christie fan but I don’t know. Unless it’s 4.50 from Paddington where Lucy the housekeeper is Miss Marple's spy?

the 4:50 from Paddington? Lucy Eylesbarrow goes to work as a housekeeper in order to find a body. Think it is technically Poirot but he’s not in it much

It's the Secret Adversary! I always forget the Tommy and Tuppence ones because I think I don't like them as much but I did enjoy The Secret Adversary. Time for a re-read.
Thanks everyone.

4:50 from Paddington. That’s what the book was called.

there was an adaptation with Amanda Holden in it.

I have to say, op, if it is any of those mentioned here then I advise moving on and rereading Five Little Pigs or Murder at the Vicarage as all the ones posted here are bobbins. 4.50 from P is especially poor; Miss M solves it by ESP apparently

Well done @Ikeameatballs!

Thanks clary. I've read every Agatha Christie, many of them more than once!
I love Murder at the Vicarage but I don't remember Five Little Pigs clearly so that's one to add to the re-read list.

Ooooh Five Little Pigs is arguably the best! Tho I do love Hercule Poirot’s Christmas and also Crooked House.