Si's apartment is clean, comfortable, stylish, spacious and has everything you need. There is a very comfortable superking(?) size bed with the best feather duvet and pillows! The kitchen is well equipped and all the ingredients for breakfast are provided. We even had milk delivered to the doorstep! The TV has Chromecast and other techie things I didn't know about! Comfortable sofas and snuggly throws ... just the ticket after a hard days sightseeing! Although we didn't get to meet either Si or Theo, Si left a bottle of wine for us as a welcome and was always very quick to respond to messages and make recommendations.
The area is quiet and green - you wouldn't think you are less than 30 mins from central London; we particularly enjoyed taking the Thames Clipper up the river to see the sights. The trains from Maze Hill to central London are just a short walk away but if you don't want to walk then Greenwich and the pier are only a short taxi ride (Uber cabs were brilliant - thanks for that suggestion Si) and there are plenty of cafes and restaurants both in Greenwich and Blackheath. The park and Greenwich Observatory is not far away either.
All in all I heartily recommend Si's apartment as a base if you are visiting London.