Around since the 1970s - Vauxhall have had plenty of time to get their act together on these.
I know nothing about car engines but these links will convince you that your car does have an EGR valve - otherwise it would fail emission tests...
http://www.asashop.org/autoinc/nov97/gas.htm
http://www.automedia.com/Exhaust_Gas_Recirculation_Valves_Explained/ccr20060101eg/1
http://en.wikipedia.org/wiki/Exhaust_gas_recirculation
Peccavi
March 2009