On 23/12/2020 14:27, John Rumm wrote:

snip

However it sounds like all you need is a spanner to hold the body of the
fitting in place while you tighten the nuts.

My thought too. Perhaps 3 spanners and 3 hands needed? Though you should
be able to work from one end to the other with just two, keeping the
last fitting or nut stationary.