I didnīt know this tools was available until I searched at Davidsilverspares in the UK. The partno are found in the beginning of the old shop manual. Several other tools are also available. It took them a couple of month to deliver this, but I finally got them today!
I guess you have your own tricks to compress the piston rings, but its kind of nice to be able to use the original equipment. Original service tools is somewhat like filling the bikes tool bag with correct tools.
The partno is 07954-3000000 (original no 07032-30001) you could search both at David silver.
They came as a pair of pliers and feels good with really strong springs.
I will try these when i start to reassemble E #7384 soon.
/Ken