Will my ancient farmhouse be free from inheritance tax?

I have heard that I can place my house within a SIPP. Please can you clarify exactly what a SIPP is and advise me if it would be a good idea to place my house in it?

My lovely 18th century cottage is in need of a full scale overhaul and I wondered if I would be able raise about £60,000 by taking out a mortgage on the property in order to fund the work. I don’t have a mortgage at present and the property must be worth about £450,000.

I have heard that if I opened my house to the public on one day every year that it would automatically become exempt from inheritance tax. Is there any truth in this?

I have recently discovered that my home, which is listed, was extended by a previous owner who had not sought the necessary approvals. Is it possible that I might be forced to return the property to its original form? If so, can I make a claim for the costs of this remedial work against the previous owner?

I live in an old cottage with many original historical features. Will it be adequately covered by a standard policy purchased online?

Can replacement windows to a house built in 1865 be VAT-free as new work or do I have to pay the VAT?