Beware. It's a lot more expensive than your local ...

Beware. It's a lot more expensive than your local private Taxi service because black cabs aren't usually that cheap and then you are paying gett on top of your taxi fare.

Another thing worth noting is that if you put the exact destination, gett app gives you a fixed price which is usually higher than the meter cost just in case there are road blocks or congestion. That fixed price does go up which I learnt recently as the taxi driver took
the longer route so there is no such thing as fixed price promise
My honest advice, use uber or your private taxi service. I know these private companies are putting black cabs out of business but then private companies are more affordable.
Use your free credit with gett for short journeys and then delete the app and use your local private taxi company.