Follow-up: Having attempted to sign up for cex.io, I found it is closed to me, as I do not have a mobile phone. Just a landline. So, scratch another site off the list. Funny, I sensed it wasn't for me, and now I know. Thanks anyhow. 
Have you tried to follow the sign-up at cex.io but omit entering a phone number? You may be surprised!
Do not click this person referal link and joins cex.io
Unless you have an interest in day trading or high frequency trading cex is no place to make more btc than you put in.