Just caught up with thread.
Have little to add, except that happy is absolutely correct on every point, especially the previous post.
I get the impression your architect is very green and is following the contractor's lead, which is the antithesis of of what their role should be.
They are supposed to be ensuring the whole process is fulfilled safely, responsibly and with due diligence to the design and construction process, as set out in the JCT and contracts.
I really would report to the ARB on this one, and suspect that a stiff legal letter to the architect may get them moving properly. They may just pass the whole lot to their insurers though which would be a risk.
Not sure if I missed it, but do you have a site meeting date yet?
Also, there will be site meeting minutes from the architect which may be worth requesting so you can get a feel for the chronology.
I honestly think that you should be instructing your architect to sack the builder for breach of contract and appoint a new one to finish the works.
You can continue to follow up with legal action for the additional money it will cost.
I really don't think you can trust the builder to so the work to a good standard or to even get back on site.
This is truly shit for you. It's worst nightmare territory for a build programme and can be such a headache to resolve, especially when the architect is not carrying out their role.