Chain of representation Australian Grant

Hi everyone,
I need some assistance on a probate matter. Husband (H) and Wife (W) are domiciled in Australia, they moved there in 1980’s.

W died in 2022, and Probate was granted in Australia. W has assets in the UK, including a property and bank accounts. Her Will (made in Australia) appoints H as sole executor with her 3 sons and accountant as replacements.

We applied to reseal the Australian Grant of Probate. This application took months at the Probate Registry, and whilst it was finally received last week, H has unfortunately died suddenly.

My query is around who has authority to deal with W’s estate, and how we get a Grant or otherwise to show this.
I have been considering a Grant de bonis non. I did an application a number of years ago, but the situation was slightly different and involved an executor that had power reserved, which we don’t have here, only replacement executors.

My next thought was the chain of representation, and that perhaps we need to wait until executors for H’s estate have proved his Will and received Grant of Probate in Australia, and that those executors would then have the authority to administer W’s estate. Has anyone dealt with this in practice? I’ve only ever read about it. Are institutions (for example the Land Registry and banks) accepting of this? I also wondered if the fact H’s Grant of Probate will be issued in Australia would break the chain?

Thanks for your help!