Correct me on your facts if I take them wrong anywhere, I found the post hard to read (must be too late for me!).

A lot of people are very misguided (both landlords and tenants) about their rights in a tenancy.

A landlord needs to give 24 hours written notice if they wish to conduct viewings, carry out repairs, do an inspection, etc. However this is 24 hours notice, not 24 hours automatic permission. There is a right to what is legally termed 'quiet enjoyment' which is awarded to a residential tenant. Your landlady will probably say 'well oh you signed to say that anyone and everyone can come into your home whenever they like without notice'. A tenant can sign any clause in an AST saying whatever the landlord fancies, but that cannot and will not override statutory rights.

A landlord can enter a property without notice only in an emergency. There has been quite a lot of legal writing on this and it basically means an emergency. A broken window frame does not in itself, constitute an emergency. I think a hole in a window pane may be treated differently as the property would be wholly insecure from both elements and outsiders, but a case for the facts nonetheless and aside from your argument. An emergency is a matter like, a gas leak. That is an emergency as everyone might die. Though, interestingly enough it does not include to conduct the yearly gas check that a landlord is legally obligated to carry out. The courts often find that repeated requests to carry out said check is sufficient to avoid punishment for non compliance.

Worst case scenario if the matter is unsortable and she asks you to leave/you want to leave (I'd be out asap after finding that lot out) you have certain rights but also certain obligations. If you are still in your fixed period (eg 12 months) the landlady cannot (in the absence of any section 8 etc ground, such as 8 weeks arrears of rent) evict you from the property. She cannot evict you from the property without a court order regardless, any action amounting to such can be termed 'illegal eviction' and reported to the police (it is a criminal offence) the tenancy officer at your local council (they have the power to prosecute). This includes changing the locks so you can't get in, getting someone to remove you without a court order, telling you your tenancy is over and goodbye, etc. She can however provide you with a section 21 notice to quit (but these are often unenforceable, quite tricky to issue, many landlords get them wrong).

If I were you, I would change the locks to the property, keeping the old locks so you can change them back at the end of your tenancy. Your tenancy agreement may prohibit the changing of locks, but would only be discovered if your landlady tried to gain access to the property without your permission.

I would also ensure that I wrote a recorded delivery letter (and keep the slip) to her, revoking any implied permission to enter the property. State that entry can be arranged at a convenient time with yourself and not without such permission as you do not, under any circumstance, wish anyone to visit the property without you being there. Add in the letter requests for reimbursement for items which have made you out of pocket, eg the wooden bed. Do not anywhere state that you are witholding rent to recoup monies as this could be used against you in section 8 proceedings and the witholding of rent is frowned upon considering it is the tenant's only real obligation in a tenancy (quite a lot of the others have found by the OFT to be unfair, some totally ridiculous ones I might add).