Let me start this article off by stating that the surface pressure went over the 1050 hPa at a wide number of sites across the southern parts of England and Wales, but I have my doubts that the Mumble lighthouse (#03609) which has figured so prominently in the charts over the last 12 hours or so should have. Here are the recent barograph traces for stations to the west of the Mumbles, that’s Pembrey Sands (#03605), and St Athan (#03716) to the east of the Mumbles for the last five days. For most of that time the Mumbles pressure in blue is the highest of the three stations, I don’t think that should be the case, sometimes maybe, but not consistently higher than the other close by stations like this.
Here is a zoomed up look at the trace for the last 30 hours or so, and again the Mumbles always has the highest pressure of the three. My guess is that the pressure sensor in the AWS at the lighthouse is reading at least 0.5 hPa too high. It maybe that the sensor calibration at these kind of extreme levels is just a wee bit out.