Ask HN: How to research about a company in UK before accepting job offer

I have been offered a role as a developer in a UK based, privately owned company. It's a fairly big company with ~2k employees. I will be working from their Indian location. Is there any website which could help me understand more about the company, other than glassdoor, their official website? I am looking for how healthy is their position is in the market, general outlook about how the company is doing etc