How do I stop notifications from one calendar?

I have a number of calendars subscribed in Thunderbird, some external ones along with my own one, One is an Awareness Days one. That is one I like to glance at daily, but at midnight GMT/UCT the blasted thing causes a whole series of notifications to pop up, one after another, one for each awareness day the following day is - and some days that's quite a few. It's incredibly annoying when I'm in the middle of something and am interrupted by the notifications. i want the calendar for me to glance at when i want to; I do NOT want the notifications from this calendar, but do for e.g. my personal calendar so can't globally turn off all TB notifications, I have: 1 in calendar tab, in the list of calendars clicked on the mute icon so it's showing a bell with a line through it and says it is muted on mouseover. 2 In its properties> Edit Calendar, unticked Show Reminders, have nothing under the Add notifications. 3 Following a suggestion from the Google AI, changed TB to use its own notification display rather then the Windows 11 one. But no effect: every midnight I get the damned parade of notifications getting in the way of the 3D CGI art I'm working on. So how do I stop the notifications from that one calendar (other than unsubscribing from it)? TB 158.0.1, but this has been going on for a long time and a lot of TB versions. Windows 11 Home 26H2