The no deposit bonus works like any other but comes with just 5x wagering - that's the lowest of any on-line casino that I am currently aware of which makes it a great shame that everybody isn't able to take advantage of the deal. I'd almost go as far as to say it's worth signing up at the real casino in order to participate in this promotion but I guess that would be a little extreme if you don't live within close proximity to a Grosvenor! If you do like to visit the land casinos though it makes a lot of sense to choose Grosvenor next time around.
The second part of the bonus is a post wager style deal - just like the 5x wagering this kind of bonus arrangement is becoming extremely rare these days. The way it works, you simply make a £20 first deposit then wager your balance five times, and the bonus will then be added to your casino account as real cash - no further wagering required, you can even go right ahead and withdraw at that point if you wish.
Grosvenor do put out no deposit bonuses for non existing customers from time to time and I have a friend who managed to find such a deal although it was a long time ago now.
As far as promotions go this has to be one of the best around, and if you are a regular player at the casino they also like to send out further bonus codes often with 1x wagering. Overall I think Grosvenor is a hugely underrated casino and wouldn't hesitate to recommend them or this bonus to anybody!