I wouldn't recommend sc5 to my Grandma.
That's probably unfair on the tyre. I'm sure on a small family hatchback, they are probably good.
Just unsuited, IMHO, to an Omega.
Unless your grandma drives an Omega

I do feel, worry even, that the current crop of tyres, which seem substandard compared to the previous generations, and being manufactured to get the 3 specs that have to go on labelling, ie, noise, wet braking and economy. Whatever committee of morons came up with those specs should be strung up and shot - surely the number 1 priority of any tyre is grip.
As to SC5 specifically, on an Omega, I don't think that 3k out of a set of fronts, and 6k out of a set of rears is anywhere near acceptable, especially given the easy life they had. At £700 for a set of 4, its unviable as well.