I just washed this yeast this week from a Northern English Brown, and tried a new washing approach due to the high flocculation. Trying this new technique was also motivated by my not having a big enough jar on hand, and washing from a bucket primary.
First, I added a gallon of water to my primary bucket and swirled it up, as normal. After letting it settle a bit, I carefully poured the slurry through a sanitized funnel into a gallon jug, and covered it with sanitized foil. After about 10 minutes, this was the result:
You can see that even though the trub is still settling out, the yeast are already sinking away from the surface. I then took a sanitized turkey baster and carefully started to suck up the yeast layer, depositing it into a sanitized growler. I ended up with about a quart and a half of slurry, which I presume is nearly pure yeast. I'll admit that it's not the most sanitation-paranoid way to do it, but it seemed to work. I was left with a good inch and a quarter of very solid yeast in the growler.