You're asking for costs for an item without a specification, working methods or preparatory works.
Even the design of foundations and slabs are specialist these days in terms of location of insulation to eliminate rising wall cold bridges, provision of radon gas collector boxes and evacuation pipe, radon gas barrier membrane and collars, etc.
You need to get this properly specified by your architect with a comment from the engineer and in particular the detailing of the foundation and superstructure and how you intend to address the matter of differential settlement or prevent it.
Building compliantly is not an optional extra or additional works, it is the law.
Get your architect to draw up what you want to build to tender drawing specification and go out to three builders and get prices.
Should be simple enough to do.
ONQ.
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All advice on AAM is remote from the situation and cannot be relied upon as a defence or support - in and of itself - should legal action be taken.
Competent legal and building professionals should be asked to advise in Real Life with rights to inspect and issue reports on the matters at hand.