How would you defend your home in the U.K. against a home invasion without a firearms license?

I successfully defended my home in Manchester with an Ikea Billy bookshelf on two occasions.We lived in a building with a lot of drug stuff around it and felt unsafe at night.

So what should we do?

There was an empty bookshelf that fit between the door of our apartment and the wall across from it on the floor.We lived there for six months and did that every night.

On two different occasions.