Extension of time application has been submitted and the 12 week period has expired what is the contractors next action
There is useful guidance on this in the case of Henia Investments v Beck Interiors.
In brief, whilst the Architect/CA is in breach of contract by failing to grant an extension within 12 weeks (although they would probably argue they had insufficient information), nothing much turns on it.
The next step therefore, if negotiation fails, is to take the matter to adjudication and bring the Architect/CA’s failure to comply with their obligations to the attention of the Adjudicator as it may help strengthen your arguments.