Fast roads west and dark edges along the Hogsmill
Worcester Park driving splits neatly in two. Central Road through the centre is a lit, slow, half-mile high street that slows further with parking, bus stops and crossings, especially on Saturdays, and the North Cheam crossroads where Cheam Common Road meets the A24 is a busy signalised junction. Then there is the other half: the A240 running along the western side between Ewell and Tolworth where it meets the A3, and the roads along the Hogsmill Open Space, Auriol Park and the woodland corner at Dancer Dick Wood, which are a lot darker.
Those faster, darker roads are where a degraded lens costs you something real. At 50 or 60mph the distance your dipped beam reaches determines how much time you have to react, and a yellowed, hazy lens scatters its output so the useful range drops and the cut-off softens. The same lamp looks perfectly acceptable creeping along Central Road under street lighting, which is why so many drivers are surprised when they finally compare their car with a clear-lensed one side by side.
The cars here are mostly family vehicles on wide 1930s roads, many of them parked on driveways or on streets lined with cars on both sides. Either way they sit in daylight, and ultraviolet exposure is what breaks down the thin factory hard coat on the outer face of each lens. Once that goes, the polycarbonate oxidises and you get the brown tint and milky haze. Households running two cars often find both lamps on one car are worse, simply because of the way it is parked.
We assess the unit before quoting, because restoration only works on outer-surface damage. From there it is masking the paint and trim, wet sanding through progressively finer grades, machine polishing and applying a UV-stable clear coat, then checking the beam pattern and aim. The run in is Cheam Common Road to North Cheam, over the A24 onto Malden Road, then the A232 through Sutton and the B277 north, about 20 minutes.