Is Corporate Litigation Services the name of the company? Can you link me to their website? Do you have a snail mail address for them?
What have they offered to do for you and what do they want you to do for them in return?
I don't have any encouraging news for you.
Companies House shows no such company as Corporate Litigation Services registered and actively doing business in the UK. That's a bad sign as they should be there for tax purposes.
The offices are virtual rather than actual. So there is no office for this company. Nor are they one of the 7 companies actually registered in the UK at this address.
The website's WHOIS tells me that the site has only been running since December 29, 2014 and that it will expire on December 29th of this year.
These are all bad signs, and while I cannot say with 100% certainty that they are scamming, I can find no reason at all to believe that they are legitimate. All the signs of a likely fraud are there.