You should seriously consider if you can afford the cost of replacing a joist in a Victorian home before you mount this. This isn't hanging a mirror or a chandelier or something, a pole dancing pole is going to exert a lot of forces in different directions. The joist you find is likely incredibly old and dry. Do you really want to risk drilling holes into that and putting it under varying loads?

A freestanding pole would cost less than a repair and you can easily move it to a new location when you move.