Access to Shed

Access

Hi

I have rented my house to family. My builder put a door on the shed at back of garden. He was meant to give me the key, but gave it to tenant. I had told tenant they have no access to shed. When he got the key, he started to make use of the shed. I got the key back, because new door would not open. Builder has fixed door. Tenant has said to give him key and he will remove his stuff from shed. Ofcourse he will never give me key back.

Other problems are that I laid new grass for garden, and they are not cutting it as we had discussed.

Bathroom had leaked water to downstairs. I had found out reason because that were letting water splash out of bath and not using curtains inside bath. I have told them they will have to pay for repairs, which they refused.

I do not feel they are looking after my property. If they were looking after property, then I would not mind them using the shed, but now I feel they are taking advantage

Can I revoke there access to the shed?