Some hgvs only recently went to metalastic bushes from greasable shackle pins.Metalastic Bushes ( AKA rubber ) are 1960's tech, the degrade, split and wear.
Supapro Blue all day long, see my build thread. Doddle to fit no press required
Fitted all round to my TD5 90, simply the best you can buy...
Never see poly on hgvs, tells me all you need to know about them.