Engine light is on
Connect OBD reader = P0130 = pre-cat lambda sensor
changed sensor and light still on

Can anyone confirm:
1) There is only one lambda sensor up behind the engine? I could only see one so changed it
2) The engine light should go out after fixing the problem? It has not gone out and I even disconnected battery to hope to clear fault from ECU

any help appreciated

Van is 2012 2300 130bhp

Use a code reader to clear fault code, light goes out unless fault still present.

Sometimes the light may go out after a number of runs with no faults.

Sometimes you have to clear the fault code using code reader.

many thanks - that makes sense

do you know if there is only one sensor?

Using MES in simulate mode
f7 Ajustments
REPLACEMENT OF LAMDA SENSOR
This procedure must be executed in case the Lambda sensor is replaced. It will reset the MAIN injection quantity correction values in relation to the Lambda sensor signal in the control unit.

So if you replace it as well as erasing the code you have to tell the ecu there is a new one
What code reader have you used / vehicle type
Looking at MES and AlfaOBD it is not obvious there is more than one.