Builder wanting a LOT more money, already had almost double time!

thearchitect

All but the most simple of construction work is a potentially complex operation: statutory consents must be obtained, detailed proposals prepared, tenders sought, and finally the project delivered on-site. For that reason it is wise to involve experience professions - architects, surveyors, and so on as appropriate.

In this case, I infer that OP has not done that. The design team were on a partial service with no site duties, Building Control seem to be envisaged as a stand-in, there has been an ad-hoc form of contract, and changes have been made on-site. The contractor has, on the face of it, been difficult.

It is easy to tell OP what he should have done, but that horse has bolted and it will benefit nobody. He needs to be pointed in the right direction.

OP, let me repeat a few points as I don't think you're listening as closely as the situation merits.

Firstly, you need to determine the quality of the work completed and quantum fairly arising. That is not Building Control's job, even in part. My advice is that you engage your architect to do so as a matter of some urgency. Three weeks is not a particularly realistic timescale in a dispute situation. This will incur professional fees, but by the sounds of it you are looking into the proverbial black hole.

Secondly, you must get professional legal advice on the contract and remedies arising therefrom. I understand from your posts that your insurers are helping with this under your legal expenses cover and encourage you to progress this as quickly as is practicable.