Engine mounting insulators

[Sanity Clause]

I don't know which bushes are fitted to the car, (they are rubber, though) but it shouldn't make any difference when the car is stationary.
The vibration is being transmitted from the engine, not the road.

It's possible that they are heavy duty items, after all.
Does anyone know of any cheaper alternative replacements?

In the meantime, I've got some Ford Escort/Cortina rubbers in place.
These seem a little too soft, though, and possibly allow a little too much engine movement. It might be worth squishing the rubber a bit more, though.