Could Commonwealth dockyards have accommodated HMS Hood?

Could Commonwealth countries have built dockyards large enough for HMS Hood?

Yes, if they had been willing to make the necessary long-term investment in dockyard and supporting infrastructure.

Physical possibility was not the binding constraint. A sufficiently large dock could have been created in a Commonwealth country. The deciding issue was whether governments would fund the dry docks, machinery, workshops, transport links, and skilled workforce required to support a capital ship. Australia theoretically possessed dry-dock space for HMS Tiger, but that still did not supply the complete repair system around the dock. Fitting a hull inside a basin and maintaining the warship once it was there required different levels of capability.