Fixed Length or Variable Length Hiking Poles?

I seem to have lost my old MSR carbon trekking poles and with a planned walk of Wainright's Coast to Coast Path in the UK coming up next year I need to do something about poles. Massdrop has Black Diamond's Distance Carbon Z polesas a drop at a pretty reasonable price of ~AU$132 delivered. These poles weigh 142 grams each.
However these are fixed length poles which I have no experience of; hence curious to know what more experienced users of poles think about going with say these Carbon Z poles or an adjustable pole such as Black Diamond's Distance Carbon FLZ which weighs in at 173 grams each and cost ~$175. To be honest I cannot remember every adjusting the length of my adjustable poles when walking so maybe I would be happy with a fixed length but ...
Thoughts?
However these are fixed length poles which I have no experience of; hence curious to know what more experienced users of poles think about going with say these Carbon Z poles or an adjustable pole such as Black Diamond's Distance Carbon FLZ which weighs in at 173 grams each and cost ~$175. To be honest I cannot remember every adjusting the length of my adjustable poles when walking so maybe I would be happy with a fixed length but ...
Thoughts?