Good Ideas 60 Second Sink Unblocker (500ml) | Easylife
Mr Muscle Drain Unblocker, Sink & Drain Cleaner, Fast Acting Heavy Duty Drain Gel, Dissolves Clogs, Works 3x Better Than Bleach, Safe for All Pipes, Duo Pack (2 x 500ml) : Amazon.co.uk:
How to Unblock a Sink | A Drainage Engineer's Walk-Through