I have a focus Ghia 1.6 TDCi with engine system fault showing. Put a mates fault code reader on and it said it was vehicle speed sensor A. Think that means intermittent. Purchased what I thought was the correct sensor. Go to fit it and I cannot locate where the sensor is on the car. Any advice on where it is and if I purchased the correct one. Photo of the item I purchased.

No idea where it goes or if it looks like that. But did you clear the code and see is it comes back when you drive it again?    Also it might just be dirty connections in the wiring plug that needs a clean.  It may be that it does need a new sensor, but buying it without knowing where it goes or checking the connector to it may have been premature, I am not saying a definite waste of money but so far you can not be sure it needs a new sensor. 

The Focus MK2/MK2.5 does not have a Vehicle Speed Sensor (VSS). On the Focus MK2/MK2.5 the speed is calculated by the ABS module based on the wheel rotations (measured by the ABS sensors) and the programmed tyre size.

3 hours ago, Dlg18792 said:

1.6 TDCi with engine system fault showing. Put a mates fault code reader on and it said it was vehicle speed sensor A.

If the car has ABS, then as Wilco says, the speed is taken from the ABS system, and there is no VSS sensor. And I thought all Diesels had ABS.

If so, then I think you need to use an in depth diagnostic system like Forscan, that can read codes and values from the ABS module. Speed sensor errors can be a result of communication errors between the ABS and the ECU, which could be a bad connection somewhere.

If the car does not have ABS, then the VSS sensor would be mounted on the gearbox, close to where the driver's side drive shaft comes out of the gearbox. It is in the differential section of the gearbox unit.

I have never seen A Focus MK2/MK2.5 without ABS. 

As far as I know European versions of the Focus MK2/MK2.5 have ABS as standard. In some other  counties (Eastern European countries, Russia) low spec versions of the Focus MK2/MK2.5 were available without ABS.