This is indeed astounding and unprecidented - the court ruling, that is, not proroging Parliament to avoid its scrutiny. (There was a much more clear-cut example of that at the end of the Major administration where he suddenly prorogued Parliament for the entire three-week period between his announcement and the general election, most likely to avoid scrutiny of a corruption scandal involving his party. He was one of the folks who submitted briefs in support of the claim that this prorogration was unprecidented and unlawful.)