Today's Choghadiya for London — the eight day and eight night periods (Amrit, Shubh, Labh, Char and the inauspicious ones), to pick an auspicious muhurat in your local time.
The day gets eight Choghadiya periods and the night another eight, each an equal division of London's sunrise-to-sunset and sunset-to-sunrise spans. Their order rotates with the weekday, and because the two spans are rarely equal, a daytime period here is usually a different length from a night one on the same date.
London runs on Europe/London, not IST, so an Indian panchang does not transfer here directly. At 0.13°W the Sun peaks about 1 minute later than the standard-time clock reads. Every timing on this page is computed from London's own sunrise and sunset.
London sits at 51.51°N. Daylight here runs to about 16h 24m at its longest and about 7h 36m at its shortest — a swing of roughly 8h 49m across the year. Because the eight daytime Choghadiya periods are made by dividing sunrise-to-sunset into eight equal parts, each period in London is noticeably longer in summer than in winter. Rahu Kaal, being one-eighth of the day, moves the same way.
Timings are computed for 51.51°N, 0.13°W (Europe/London) with the Swiss Ephemeris: the day's exact sunrise and sunset first, then Rahu Kaal, the Choghadiya periods and the panchang limbs derived from them. Nothing is approximated from a nearby larger city.
No. London is on Europe/London while an Indian panchang publishes everything in IST, so the timings have to be recomputed against local sunrise here.
Because it is not a fixed clock time — it is one-eighth of the daylight span, measured from that morning's sunrise. Daylight in London varies by about 8h 49m across the year, so both the start time and the length of Rahu Kaal move with it.
No. Rahu Kaal, Choghadiya and the panchang are properties of place and date — identical for everyone in London on a given day. A muhurat chosen against your own chart is a separate question and needs your birth details.