You can find some hidden vehicles in the parks of London, such as a sooty van (Little Suzuki van with grass in the back) and a very fun golf cart parked behind huts and bushes around the parks.

Select Free Roam mode once it is unlocked and make your way onto Oxford Street from the start point. Head west past the marble arch and onto Bayswater Road (use the map supplied with the game for road names). Follow Bayswater Road westward as far as the game will allow you to go, then turn left at the blockade onto the Hyde Park Inner Road. The Hyde Park Inner Road U-bends back around to travel through the center of Hyde Park at this point. At the back of this U-bend is an open gate. Go through it, and parked outside a mansion is a Nissan Skyline GTR and a TVR. In the garage opposite the mansion is a Lotus and a go-cart.

To get the Concept Lexus and a Triad Gang Car (souped-up Honda) in Free Roam mode, in the mission where Carter infiltrates Jolson's warehouse, go to Chinatown (located in Soho). Go down into the underground garage (the same car park where the Triads and Yardies have a gang war). The position of the cars varies on each floor.