Glassdoor makes money on the back of companies by publishing reviews from fake employees. Quickly they grow their SEO so that anyone entering COMPANY reviews will find their website. Ultimately they sell Ads to recruitment companies and also aim to compete with LinkedIn.
They NEVER check if a review is from a genuine employee or someone willing to produce damages.
You can find Negative reviews from Anonymous people who have been rejected a position, while the company is not able to argue to such comments...
Glassdoor activities are illegals and they would be sued in many countries if they has offices outside California
I have used this site occasionally.
Top level Clean bill of heath on Virustotal. but report from quttera.com was that 1 out of a sample of 100 uploaded files contained a link to a suspicious ( blacklisted site) - use caution before downloading (as with any site, more or less)
Just be wary that the site is based on opinions and think about what the motivation is for people to post on here. The information is at best partials and biased, but may give you something to think about or and indication of interviewing methods before you apply for a job
Search jobs then look inside. Company salaries, reviews, interview questions and more - all posted anonymously by UK employees and UK job seekers.