What makes them seem legit?
Just a quick DD check
Despite being a 25-year old Geneva-based consultancy company, there is no company called "Gatwick" incorporated in Switzerland.
The two phone numbers listed on the website are UK and Luxembourg, not Swiss.
Their office address in just a Regus location in Geneva, which is not what you'd normally expect from a business as supposedly old and successful as this.
Once you filter out LinkedIn profiles, the only results on Google seem to be job ads in Russian based in Moscow, with a pretty modest salary.
The domain gatwick-ag.com was registered 8 days ago.
It's up to each and everyone interested in this company's services to make their own assessment. Maybe there are perfectly valid reasons for all the concerns above.
While it may look like a Russian company putting up a Swiss facade, maybe it really is a consultancy firm that's 25 years old based in Geneva, despite not having any immediately available background checks to support that image.