Evenin' All........Police warrant entry damage?

Access

Adjoining neighbours (shopkeepers)have reported a smell of cannabis growing in a flat let by me and the police have been making enquiries with a view to a possible warrant for entry. I have just given inspection notice on other grounds but haven't yet checked it out. My query is, am I responsible for costs of repair if the police barge in the door(uPVC, expensive to fix)? Another local tenant of mine has been contacted for information by the police and I have asked that he gives my contact details so I can provide a key if asked. Is this OK for me to do? Actually I believe this is a storm in a teacup as the tenants have been fine, but if it came to a forced entry would I end up with the obligation to fix the door, boarding up costs and so on? If I warned the tenants off would I be obstructing the police in the execution of their duty?