Any advice for minimoon in Santorini, Milos and London?

Hello,

We are planning a minimoon after our wedding this September for 9 nights in Santorini, Milos, and London (3nights each). It’ll be my first time visiting any of those cities.

Greatly appreciate any recommendations for activities, restaurants, etc.

Already booked accommodation for Santorini and Milos, not yet for London.

We are looking to do a mixture of relaxation and fun things to do.

TIA!