This URL will do it. Just pick preferred version:

 https://archive.mozilla.org/pub/thunderbird/releases/148.0.1/   to pick among OSs, languages...  

If you use windows, US English, 64-bit, this is the URL: https://archive.mozilla.org/pub/thunderbird/releases/148.0.1/win64/en-US/

You can also download the current Thunderbird release at https://www.thunderbird.net/download/

Thank you James. I had problems with my server which meant I had to un-install and re-install. It reinstalled the ESR version. I then installed the Release version but still had the ESR on my taskbar alongside Release. I have tried to delete ESR from the taskbar without success. How do I get rid of ESR and keep Release. David

I believe that both versions install to the same place, so the last one installed replaces the other. It may appear that both are there, but there is only one. My thought is than an uninstall would remove the release version

Thank You David. I have 2 Thunderbird Icons on my taskbar. When open the ESR is a completely different layout to Release and the righthand side is taken up with a donate request. The Release has the layout same as earlier versions. The problem is I cannot remove the ESR from the taskbar whereas the Release just goes and to get it back I have to go into windows icon and click on the Thunderbird App to get it back.

First, the layout is the same, so what you are seeing is just that one is set differently. My guess is that one of those is a Microsoft version. If you click Help>about and see words that it is an MSIX version, that would confirm it. The MS version is installed to a different location and can be safely removed. BUT, first be sure to make a copy of the release version (the last one installed), but these steps: - with thunderbird NOT running, enter %appdata% in search bar on desktop - this should bring up the appdata]roaming folder - select the thunderbird folder and make a copy of it for safekeeping - now, uninstall the MS version