Thank you Lookaway
I decided to call them up to ask if I could make a first deposit without the added first time 100% bonus but the guy said it was obligatory to take the bonus

So I bit the bullet and deposited £20. Then quickly another £40. This money went with a RTP of about 20%. So I figured that I had to continue even if I just broke even,or even a £20 loss overall. These where all on Rumpel Wildspins. My next deposit was £30 and I eventually hit 2 bonus rounds which I cleared the wagering with.
But then I checked wagering and the new bonus had kicked in and my withdrawable balance was £20 with a £750 wagering requirement
However I visited Captain Venture where I played about 200 spins,hit the bonus round then checked the wagering and found "withdrawable" £210 - Bonus £20.
So I took the £200 and binned the bonus money.
I presume it was because I didn't touch the sign up bonus money?
Anyhoo. I verified my docs before depositing so I should be safe.