Get a stihl cordless, far lighter and more convenient than petrol, I have approx 100 meters of leylandi and cut it all on one battery, I was amazed at how powerful and efficient it is, it was recommended to me by a tree surgeon.
I think mines the HSA56. But it’s similar to this
https://shop.stihl.co.uk/products/hsa-50-battery-hedge-trimmer