Where is the old computer? If your data is not on another synced device... you may be in trouble.

Sync is not a backup tool but it is a good sync/transfer/move tool https://support.mozilla.org/en-US/forums/contributors/707681#post-86895

https://support.mozilla.org/en-US/questions/1286905

What is Firefox Sync and why would you use it https://hacks.mozilla.org/2018/11/firefox-sync-privacy/

The other computer is still functional, this is an additional PC but the sync just isnt pulling through. I have my profile on several computers and its never been an issue before

The other devices are synced

From the old computer, can you see the new computer on this page --> https://accounts.firefox.com? Did you verify the sync settings on both computers? see screenshots

No it doesn't appear so

Its working now for some reason :-)

Thanks for your help

Mark it as resolved and have a nice day.