Your bonus will become forfeit, this is the staple for almost all the betting sites using sign up bonuses unless otherwise expressed that there is no wagering requirement for a specific bonus. However, with the Grosvenor sign up offer they have given their punters a 30-day period in which to 5x the bonus they have received. For example, if you deposited £20 then you will need to wager a total of £100 before you can withdraw your winnings and bonus into tangible cash.