I have a Ford Focus 1.6 2005

There is an oil leak. Bottom of engine on the right if you are facing the bonnet. 

On the right hand side on the gearbox

Not Gearbox oil but engine oil

Appears only to leak when the engine is running. No sign of oil running down engine

Any ideas?

Petrol or diesel? 

What makes you think it's engine oil rather than gearbox oil if it's on the gearbox?

Can you post a picture of it?

I bet it's gearbox oil and it's from the selector shaft seal the Ib5 is common for this and it pours from the plastic box.

Hi Folks many thanks for your message.  Yes I will check and take a photo later for you.  Under the right hand side of the engine there is a plastic box always wondered what this was.  Unclip the box and looks like something to do with the gears inside the box.  

9 hours ago, RobertX1966c said:

Hi Folks many thanks for your message.  Yes I will check and take a photo later for you.  Under the right hand side of the engine there is a plastic box always wondered what this was.  Unclip the box and looks like something to do with the gears inside the box.  

Yes its the selector for the gears if u need to change the seal here is the guide I used on my older car. https://workshop-manuals.com/ford/focus_1999_08.1998-12.2004/mechanical_repairs/3_powertrain/308_manual_transmission-transaxle_clutch_and_transfer_case/308-03a_manual_transmission-transaxle_vehicles_with_5-speed_manual_transmission_(ib5)/description_and_operation/diagnosis_and_testing/general_procedures/in-vehicle_repair/gearshift_control_shaft_seal/