Add toilet to existing bathroom?

[DRAK92]

Hi this is my first post on this forum. I’m thinking of purchasing a house but the existing bathroom does not have a toilet as this is in another separate room. The house is a period home (104 years old) and made of Yorkshire Stone.

I just wanted to know what are the challenges with installing a new toilet? Also roughly how much am i looking at in terms of renovating the bathroom (i.e. new toilet, bathroom and sink)?

Thanks for the advice in advance.