Photos not updating in Big Sur

I recently upgraded my laptop and it came with big sur.

Everything moved across seamlessly except photos.

Photos seems stuck on my laptop at the point where I changed models.

My phone and iPad continue to update as they always did but the laptop is having none of it.

It stubbornly sits there saying 'updating...' and doing nothing. This has been the case for weeks now.

How can I kick it into action?

Can I delete a file somewhere to set it off freshly downloading from the cloud where all my pictures are and begin afresh?

I use a phone hotspot to connect to the net and always have, and have no choice, and it has better download speeds than most local broadband, at least 10mbs.

Many thanks