I'm in Cambridge and know various people who work/worked there, so I'm fairly sure that those 175 include many of the remaining "early employee" group. They'll be getting a nice windfall, obviously, but it's not never-work-again money.
For contrast, founder and CEO Mike Lynch has reportedly netted a tidy £500m or so for his share of the company.
For those not familiar with the numbers, Autonomy was basically the most successful software company in the UK, and the sale valued its shares at around a 60% premium give or take market fluctuations at the time of the announcement. It was founded in 1996. HP is the currently the biggest IT company in the world.
In other words, this exit is as big as anything in its generation is going to get in my country, and if you weren't founder/investor/board level, you weren't retiring from it.
[1] http://www.businessweekly.co.uk/hi-tech/12571-autonomy-cambr...
I guess they're a bit conflicted though: YC startups need employees, and if their results showed that the early employees were getting screwed, they might not want to release them.