Hi, welcome to Just Answer. I will help you with your question.
If the problem is particularly bad, then yes, you should be able to argue that the property is not fit for human habitation.
Obviously, any landlord must provide a property that can be lived in. If this cannot, without becoming ill, then it's not going to be of the necessary minimum legal standard.
As such, you would be able to write to the landlord confirming that, because it's so bad, you're treating the situation as being a fundamental breach of contract and that, as such, you elect to end the agreement and walk away.
okay - not too sure if the property is unfit for human habitation all the time though. When the property is cleaned the problem is hidden but the mould spores continue to grow.
Well, if it's causing you to be ill, then I'd say it's unlikely to be fit for habitation! If it's short of this problem, then given you were told about it, then you're not likely to be able to claim. So, the extent of the problem is important. But, sometimes, you have to put your heath first, regardless of the law, and look after yourself.
That said, one of the ways to address this would be to get the Council in to look at it for you as they have powers to prosecute landlords that let premises that are unfit.
This is a good way to work out whether they think it meets that standard.
And, of course, their intervention/assistance wouldn't cost you anything.
Yes, I will speak with the Landlord first and see what their response will be. Thanks for the information which I will use.