I guess your Volkswagen Golf will have the standard twist beam rear suspension rather than the multi-link, which gives a much better ride. And the estate will have stiffer springs for load carrying. Not really a lot you can do except try lowering the tyre pressures slightly.

If the rear tyres are pumped up to something like 40PSI for load carrying, then letting them down to around 32 should make a huge difference (as long as you're not carrying a load).