Morris Minor Owners Club

When on the road without a load in the back, my traveller feels very 'harsh' when going over ruts and speed bumps etc. Is there any way to 'soften' the rear suspension?

Check if it's sitting on the bump stops ! Or very close to them. You need ~ 1.5/2" travel before the bump stop hits the chassis pad. Have you fitted teledampers - or filled the lever arms with thick oil ?
Most (including myself) would wish to stiffen the suspension - not soften it! Other possibilty of course is over-inflated rear tyres. When running empty you may find it better to drop them back to ~ 28 psi. With a load - I run mine at anything up to 40 psi depending on the load!

I used to use Traveller springs on my Minor saloons with 2 leaves removed.

It is easy to do. Just remove 2 of the lower leaves.

The saloon uses 5 leaves and the Traveller 7 so it will feel harsh when empty.