The Classic Tour (Blue Route) departs every 20 minutes. Passes by the London Eye, Tower of London, Big Ben, the Houses of Parliament, and more.
The Essential Tour (Red Route) departs every 20 minutes. Passes through the centre and North of London including Covent Garden, Westminster Abbey, Hyde Park, and more.
The Museum Tour (Orange Route) departs every 30 minutes. Passes by London's iconic museums such as the Natural History Museum, Science Museum, and V&A Museum, as well as the Royal Albert Hall, Harrods, and Buckingham Palace.
Check the bus route map and schedule on https://bit.ly/3qLutYU.
It was a good one and fuss free, just a bit pricey, but London being London, it’s expensive.