Rupert wrote:

I want to produce chips to make paths with, compost-making is
secondary.
Which sort of shredder does that best: spinning-blade type or "silent"
cog-wheel type?

I bought a Bosch 2200 HP ( 2.2Kw) after taking advice from this group a few
years ago. Previously I had used the spinning blade thingy's and found them
too noisy and slow..
This machine certainly gobbles anything I chuck at it and seldom jams.
The only disadvantage is that the material produced is slightly larger than
that of the blade models ....

I have a 'silent' Bosch shredder with the feed screw mechanism. I've not
used any other sort to compare it with, but I've shredded a great deal
of material which I've used for paths.

One aspect that seems to work well for that purpose is that the pieces
are of a fairly uniform size. The pieces are chunkier than the stuff my
neighbour's spinning blade shredder produces and they seem to last
longer and look better when used on paths.