Lost android phone - Needs to be replaced, but how?

[Dr Murdoch]

Mrs Murdoch managed to leave her phone on the train at the weekend, and with no great surprose it hasn't been handed in to lost property. Her insurance doesn't cover lost / stolen.

Now, she only wants to spend £100 on a replacement (give or take £20).

What is the best android phone, 2nd hand is fine (I think) for this money? Any recommended retailers or websites to use?

Cheers