Full Bathroom Addition on Second Floor

I'm looking for an architect's assistant to produce plans for installing a traditional-style bathroom to the second floor of my listed building.

The primary goal of this project is to improve the convenience of the property. Currently, the bathroom is on the first floor, and having it upstairs would greatly enhance the usability of the house. Please see attached sketch of proposed location on second floor. The bathroom would be above the existing bathroom, so a internal waste pipe would be needed to go down through the floor to connect with the existing waste pipe below. This virtual view is more accurate than the attached floorplan.
If the weight proves too much for the floor, a shower instead of a bath would suffice.

Virtual view:
https://vt.ehouse.co.uk/LmzVPBk1yQ6

Key Requirements:
- Experience working with listed buildings
- Ability to create plans for a bathroom
- Expertise in traditional design
- Strong understanding of building regulations and requirements

I have a heritage consultant in place and we aim to submit LBC application by end April.