What regstration year did Vauxhall install 3 point seat belts to all 2nd row rear seats in the Zafira? ?

I have a 1999 T reg Zafira. The centre 2nd row rear seat has only a lap belt which I can't use for any of the children. Could someone tell me the year Vauxhall upgraded to all seats having the 3 point belt? Can't afford a very new model so when they were 1st introduced would be a great start. Thanks in anticipation.|||Only came in with the new model in 2005 at '05' reg. Cheapest ones will now be around 拢4,000.