There's been a few Hercs, both 'visible' and non today, there must be something on ;-)
Whilst looking upwards for the last one I spotted a large-ish red/orange blob, possibly tapering to the lower side. Amazingly i had a pair of binoculars to hand and for a short moment watched it as it passed overhead roughly in lockstep with the broken cloud around it. I'd like to think it was a balloon of some sort, possibly a weather/research type, my viewing angle was almost underneath so little perspective. As they don't show up on trackers, how does one find out ? Wind is coming from the North and this was over London at 14.00 local today.