Aprilia S[port City Cube 300cc 2012 (UK) - Speed sensor ( magnetic pick up at rear wheel) - KenC

I have the above scooter, the speedometer & mileometer have a fault, nothing displayed, now and again it bursts into life. Can anyone with knowledge tell me the easiest way to access the connector plug to the magnetic speed sensor ( somewhere adjacent to the lockable tool box on the offside leg shield)

thank you