Getting accurate quotes

[Robbox]

My dear sister is a retired architect and she has kindly drawn up our ground floor with modifications for an enlarged WC and also combined kitchen/diner area.
I've seen her examples of works schedules and I can see how they make the tender process simpler and accurate. She doesn't want to make the schedules herself (retired and all that) so my question is what is the cost effective way to get this done? Do I have to get another architect on board or is there another route I can take?

 

[noseall]

I fully understand the need for customers to remove ambiguity at the quoting stage. But if the drawing is accurate and detailed i.e. it has plan view, elevation, section views and plenty of notes, then you as the customer are capable of noting down your requirements.

For example....

Builder to price for all building work i.e. foundations, drains (storm and foul), scaffolding, over-site, masonry, lintels, steels, first floor joists, roof carcass and covering, internal knock-through, UPVC doors and windows, internal walls (masonry and stud) finished plastering, waste removal, floor deck, skirts, architraves and window boards etc.
Include all incidental materials, i.e. sand, cement, concrete, all insulation, tie wires, DPC, DPM, timber, sealant, fixings etc.
Builder to itemise specifics i.e. garage door, bi-folding doors, staircase, roof lights, porch canopy, retaining wall etc.