For transportation, the London Underground is a convenient and affordable option. Consider purchasing an Oyster Card to save money on fares. Taxis and ride-sharing services like Uber are also available, but can be more expensive. Be aware of the high traffic in central London, as travel times may be longer during peak hours.
If you have more time in London, consider adding a day for a visit to the Warner Bros. Studio Tour to see the Harry Potter sets and props. If you have less time, consider removing a few attractions and focusing on your must-sees.