For a festive trip around London, the best route is a circle through Regent Street, Bond Street, and past Harrods, where the lights are brightest, to avoid feeling cramped, I recommend choosing a vehicle with a few extra seats, such as a 16 seater Hummer for a group of 12, to avoid overpaying, book through this website on weekdays they have transparent prices and reliable drivers, be sure to check whether bars are included in the price to avoid any surprises. The trip is worth it.