Hi Pete. I am not 100% sure but on some Vauxhalls I think the EGR valve will only Actuate with the engine Running and can be seen to be working by watching the airflow signal. ??

( Air flow signal shows on the EGR Actuator screen )

I think it might be on these corsa's as i cannot remember actuating them in the normal method and hearing them click.

H.T.H. Tony.