I've disabled Thunderforest map tile options for now. I got a notification that we have more than doubled the free usage level in the last few weeks, and to continue using them, we'd need to purchase a 95 GBP/month plan. Of course our project has no money and if it did, we'd probably not prioritize a few map tiles as the place to spend it.
I've asked if we can just use them until the quota is hit each month. If that turns out to be possible, I'll reenable them.