Yes, it was the plant before Windscale, Calder Hall, and the wind coincidentally was blowing from the SE, unusually so, taking the radiation away from the UK and just skirting Ireland and Ayr.
I hate to say, scrummy, and dampen your logic but an accident as per Japan is unlikely as the UK is not on active plates or major faults such as Japan has. So an incident as per what has happened to them is virtually unlikely. However, that does not mean other accidents could not happen - there is one other factor too and that is the strength of the "flasks/spheres/tanks" that house the reactor are very, very strong and one should remember that with this Japanese disaster there has been no rupture of the tank. The radiation levels that are being admitted are not too dangerous and are mainly iodine based and radioactive iodine has a very short "half life" meaning that within ten days, the presence is greatly reduced and within a month only barely present. The evacuations are therefore precautionary ones.
So to see Sizewell, Dungeness, North Berwick, Windscale go up, or wherever, (and also French units) a la Cherbonyl is highly unlikely. In fact, most of us have forgotten the impact of Cherbonyl, but it is still there in radiation pockets and especially lambs being born with deformities - as that radiation has been ingested - again a difference with Japan where they are trying to ensure there is no ingestion.
Hope that this alleviates the need for you to make a pack (and where are you going to head) and also rush out and buy iodine tablets to load your thyroid (the way they stop ingestion of iodine).....