Seems to be back again now thank god.
"there was an issue at their [OSM] end with Thunderforest going down, which took down our OSM Cycle and Outdoor maps. Thunderforest came back online around 5:21 AM our time this morning and those maps are now available again across our platform."
From their IG
@Tychom started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Seems to be back again now thank god.