Observed on upstairs windowsill. I think it is Ctenophora species, but not sure which one - pectinicornis, perhaps?
No interactions present.
Yes, from a quick scan of the Tipulidae gallery in Diptera.info, a female C. pectinicornis looks a good bet. The male illustrated there is more yellow.
Lat/Lng: 51.4, -2.3
OS grid ref: ST8268