How we find the cause.
We look at the existing layout against what you want, and separate the two jobs hiding inside most bathroom projects: replacing fixtures where they already are, and moving them. Swapping a vanity for another vanity in the same position is straightforward. Moving a toilet two metres means new drainage, and the floor decides how hard that is.
A bathroom renovation also involves waterproofing, tiling, electrical and sometimes structural work, and the sequencing between them matters more than any single trade. Confirm what is in the plumbing scope and what is not, and who is coordinating the order of works. Existing faults should be raised before anything is closed up.
What to send us
Share a simple plan or photos, the specifications of the fixtures you have chosen, and your rough timetable. Say clearly which fixtures are staying put and which are moving, because that single distinction drives most of the cost. Raise any existing problems now rather than after the waterproofer has been.
What actually moves the price
Fixture positions, access to concealed pipework, product selection and how much is changing all affect the scope. Keep plumbing separate from the other renovation trades when you compare proposals, or you will be comparing numbers that contain different work.