Suspension bushes

[flightmaker]

I had an MOT advisory on a couple of bushes last year:-

"Nearside Rear Suspension arm rubber bush deteriorated but not resulting in excessive movement TRAILING ARM FORWARD BUSH SLIGHT DELAMINATION (2.4.G.2)"

Offside same.

Original parts are apparently available but it would be nice to replace with polyurethane if possible. I've done some phoning today talking to Superflex and Polybush with no positives. Does anyone know of suppliers of poly bushes for the 4G please?