It is the spring time ( Last week of August to the first two weeks of September)
The London Pass is a sightseeing city card helping visitors to see the city's attractions quickly. You can buy the london pass here https://www.londonpass.com
The best way to see London is using the London hop-on-hop-off bus tour. you can get more details here https://www.theoriginaltour.com/
It depends on where you want to go, but london trains are quick and hassle free when using underground tube. you can get more details and tickets here https://visitorshop.tfl.gov.uk/
Visitor Oyster cards are plastic-type smartcards you need to use in place of paper tickets . Put on pay while you go credit that you use whenever you travel . It is the most affordable method to pay for single trips on bus , Tube , tram , DLR , London Overground, buy one here https://visitorshop.tfl.gov.uk/tfl/london-visitor-oyster-card/
Car rental is widely available across London, from the international airports, rail stations and across the city, compare prices with Rhinocarhire.com
Companies like https://www.enterprise.co.uk/en/car-hire/locations/uk/london.html and http://www.arguscarhire.com are helping visitors to book cabs in lodon. check their websites.
You need to go to places like Mayfair, Covent Garden and West end to find some nice restaurants.
Leicester Square is one of the busiest areas in London with good nightlife venues.
Places like London Eye, London Transport Museum, Tower of London, London Zoo, Madame Tussauds, Buckingham Palace, Pollock's Toy Museum, Sea Life London Aquarium and Harry Potter: Warner Brothers Studio Tour are the good ones with kids.
London City (IATA:LCY), Heathrow (IATA:LHR), Gatwick (IATA:LGW), Lutton (IATA:LTN), Stansted (IATA:STN), South end (SEN)