Mine has done much less than yours !! What I don't understand, is, if there were premature breakages at an early stage, why did Vauxhall keep churning out Omega's with the same fault for year after year. Surely they must have upgraded something.
The fault wasn't with the parts it was with the servicing schedule and dealer greed.
Basically the belt is good for the original 80,000 mile schedule... As long as the pullies were replaced at the same time.
Problem is dealers were charging for the full kit but only fitting the belts. The obvious result being that the pullies failed soon after. Much like VW and their water pumps.
To avoid further issues GM simply halved the interval and insisted that the pullies were changed at the same time. It was more of an issue for the Vectra B due to the sheer number of fleet cars around but it.tarnished the engine somewhat.