TENANT NOT ALLOWING INSPECTION

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I have a set of tenants of which he works away and she is at home with her 2 children. They have been in 3 years and basically after one year and all being well I done another inspection after 6 months. OMG she had painted the lounge and radiators black and uplifted my carpet and replaced with a cheap flooring. Painted the bedrooms blue! The fitted wardrobes were gone apparently placed in his mams garage for safe keeping together with the carpets. I think they sold them! To my horror they also had gained a dog and 2 cats! I explained to her that they had breached their tenancy agreement however she said that she had the dog for protection as her x was out of prison! I have continued to let them llive their and wrote a letter explaiing that the property was in a poor condition and a state of disrepair and all of the above needed to put back to normal. I now do every 3 month inspections. It is due this week and now I have had a text saying she is suffering with mental health and that they want it done every 6 months!! He works away and she does not want me in the house with her! However she allows the gas man in with no problem. She still takes the children to school and to dancing classes and is out and about daily so why not let me use my key?? I am so fed up with her attitude as on my last inspection she did not even say hello and put her head down and ignored me and he done the talking!! I honesly feel llike serving them notice. HELP thank you