When in lobby, top left you'll see "My Account" or "Account"
Click this and it will show %age wagered.
The figure remaining to the right of the percentage completed figure (lets use £20 as an example) is what you need to wager x 35 so in this example £20 x 35 = £700.
I had a good run at this casino last night, peaked at £400 (from £25 deposit) went to bed with £300 left and 55% of wager done.
Today turned to rat shit, eaten alive my every slot I tried, cashed out £90 which I suppose is over 3x deposit but still a tad miffed
Good Luck!