Hi Tony.
A well trodden path this one now. Couple of options. But it depends on your personal taste.
Generally people are happy to pay a small trade off in harshness of ride, for a more accurate handling and stable car. Elites are comparatively soft and wallowy in the suspension dept. compared to the rest of the omega range. This in pursuit of comfort almost above all else. Hence the trade off with poly is worth it, if you're a progressive driver.
If you prefer comfort though, then fitting like for like is the way. Although the life of oe parts is limited, as rubber wears and fails much quicker than poly ever will.
...? 
Depends how you feel the car drives too. Any issues with it?
Hi Chris,
If I'm honest, I don't find it too wallowy - not for such a big car. And the roads around here... well... I think there are only a couple I drive down that
don't have potholes!

Body roll never bothers me, you just have to compensate. And most of the time I drive casual anyway. Do poly bushes really make that much difference to the ride quality? The only experience I have of them is from having them on my E30 - and that had sport springs/shocks and a 30mm drop, so it was harsh anyway

Also, some joker put directional tyres on the front so the handling's all shot to pieces anyway.
I just figured that, after 100k+ miles, it might be worth freshening up the bits that bear the burden of making it go in a straight line and round the curvy bits. How long would OE bushes last me - I only do about 3k miles/yr in the car?
There's a slight clunk-sensation sometimes when turning the wheels, when stationary. I can't find any steering leaks so I just guessed it's likely something in the suspension warn - ball joint maybe? If it is then I might as well refresh some other bits.
T.