Yes that is correct...
She's demanding that I pay her, her deposit back. I've refused on the grounds that there was other solutions...
That is quite right.
You would be liable for the £50 of course.
But if she refuses to get it transferred she has failed to mitigate her loss
That means minimise it.
You should write and set out your position. so that everyone is clear.
Say you are willing to transfer for the £50.
But that if she refuses she is failing to mitigate and therefore you consider that you wont be liable.
Can I clarify anything for you about this today please?
That's everything! Thank you so much for your help!