MIL has been strong-armed into signing a tenancy contract

[worriedaboutmymil]

My MIL lives in Northern Ireland where she has lived in a little rented house for the past 12 years. The house was sold a couple of months ago to a local property company. Earlier this week a man from the property company arrived with a new tenancy agreement. He was polite but forceful and 'in a hurry', he needed her to sign the new agreement there and then. My MIL is in her 70s, lives on her own and was naturally flustered. She signed the doc, which included a rental increase from 500 to 600 p/m. He didn't leave her a copy. He also insisted on a new deposit (she hasn't received her deposit from her old landlord), which she paid.

We knew the property was being sold but this part has only come out today because she didn't want to worry my DH and my SIL. We live in the south and SIL lives nearby MIL.

We are all worried MIL has been hookwinked/strong-armed into signing this new contract. We don't have the details of the new agreement and don't know if we can back out or do anything. SIL will be going to Citizens Advice on Monday, but I though I'd check with you lovely people to see if it's legal and above board. I'm not familiar with the UK rental rules as they're quite different from down here.
Many thanks for reading!

[wowfudge]

I am not sure whether her existing tenancy should just have continued with it transferring to the new LL, but she sure as hell should have had any rent increase proposed in advance. Also she should have either had her original deposit back or it should have been transferred. No way she should have to shell out before the first was returned to her. And of course there should be two identical copies of the tenancy signed by both parties and one left with her.

I would say she has been pushed to sign under duress and this is a strongarm tactic which is unpleasant and unnecessary. She should complain. It doesn't bode well but it may be just an over zealous employee who doesn't understand the law in these things.