Mould..

Tenancy Deposits

One of my tenants complained of mould in her bedroom. I provided her with a dehumidifier but she didn't use it. She also refused to open windows or doors to keep her room well ventilated - for over a year.. so the mould took hold. 

After her second complaint, I immediately engaged a mould expert who removed the mould and wrote a report stating that the mould was not caused by structural or damp issues but by condensation and a lack of ventilation, i.e. lifestyle factors attributed to the tenant. 

The tenant has since moved out. I paid £900 to have the mould removed and repainted with anti-condensation paint. I withheld £250 of her total deposit (£500), as she was clearly to blame. I felt this was fair. 

The other tenants in the house are willing to write a statement to confirm that she did not open doors, windows or blinds or use the dehumidifer. 

This will go to the deposit scheme adjudicator.. Where do I stand given that new Government 'guidnace' has been published on the landlord's responsibility around mould and it shouldn't be blamed on 'lifestyle choices of the tenant'?  I believe this hasn't been legistlated yet, it's just guidance. 

I called the NRLA hotline and the chap advised that she doesn't have a leg to stand on, as did the mould expert.. however another enquiry to the NRLA said the guidance  that the tenant cannot be blamed will stand - so I'm unclear on my position. 

Thanks.