I've used plug in electric saws. For what they are they work fine, be sure to keep the chain sharp. A hand file will touch them up pretty quickly if you don't let them get too dull.

I have used a saws all with a coarse blade and a 500 W hand carry generator with good results.

Now I have a 70's McCulloch promac 700 rescued from the scrap pile and fixed with $ 25 in parts.

For high stuff a weed wacker ( strimmer for you Brits ) with a stick saw attachment works for high stuff. ( another scrap pile rescue )

A battery powered one would tend to eat batteries pretty rapidly ( as in wear them out through many charge / discharge cycles )