2011 Bocanegra gearbox leak

[Jacktennent01]

Hey, so I've just had my bocanegra done for a major service and brand new spark plugs and coil pack which has set me back a pretty penny. But halfords have told me I have a leak on the gearbox. The spanner light is flashing along with the gear im in. Anyone had this problem, if its serious and what can I do to fix it? Thanks