Thats the one . . . you say the "compatibility check" said it was not suitable for your omega
I just done the compat check with your model 2.6 saloon 2002 details & it said yes .
As I recall, a few on here have used that supplier & have been pleased with the quality.
LCO's guide above is about right . . .watch out for the 2 very small O rings when you disconnect auto box pipes above the rad on drivers side . as you lift the block connector up after undoing the 1 torx bolt , these O rings can drop out if you are unaware they are there.
Also the 2 rad switches down passenger side ( which you will have to change over from old rad to new) are a bit tricky to disconnect & re connect . I pre marked the underside of the connector so looking at the mark from underneath , I knew they were in the correct position to slide straight in to the switch
Some rads pull out easily others are a barsteward to get moving . Never understood why that is
HTH.
**Note to myself . . .about time we had a rad changing maintenance guide with pics on OOF