According to a Fermentis presentation, genetically it falls in the British family of yeasts - which makes me think that it's a dry equivalent of something rather like WLP540, allegedly from Rochefort (who had some problems re-establishing after losing their kit to the German army in WWII, and ended up raiding the Palm yeastbank in the 1960s so it's plausible they ended up with a yeast that is not conventionally "Belgian"). So it's not really the yeast you want if you're looking for banana and clove, but is well suited to big dark beers, and might be an interesting choice for some British styles.
Don't worry about expiry dates on dry yeast, they have a half-life of 10 years or so. As it happens I pitched some September 2017 BE-256 into 13l (3.5 US gal) last weekend and went away, by the time I got back 4 days later it had ripped through 1.066 wort with 83% attenuation (and had actually blown some of it out of the bucket).
Doubling down with more of the same doesn't usually work. It's worth checking with a hydrometer to see whether it's really at 1.037 or whether it's just a Tilt issue. Rousing and a bit of extra warmth would be the usual place to start.