Minicab For London / Minicabs UK / untrustworthy
Used their app for booking twice and booked through their website several times. I must confess, using both of them is a complete nightmare.
They are easy to use, they are just non-working.
My cabs never arrived usually or were late. Don't ask me what I was thinking when I booked them knowing they are untrustworthy. Probably I was always in a rush and did it automatically hoping they would get me to places.
Oh well. What I wanted to say is that if you don't want to be late, use different taxi services. I deleted the app and will follow my own advice.