<?php
 
$url = 'http://w...content-available-to-author-only...e.com/cars.php?postcode=CV2+5AS&distance=&make=&min_price=&max_price=&category_type=&body_type=&fuel=&colour=&transmission=&year_of_registration=&mileage=&engine=&doors=&seller=&keywords=&sort=PRICE_LOWEST&referer_url=http%253A%252F%252Flocalhost%252Fselling%252Fcars.php&trader_id=0&case=ADVANCE';
if(filter_var($url, FILTER_VALIDATE_URL)){
    echo "OK!";
}else{
    echo "Not OK...";
}

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