Gtech Cordless Grass Trimmer GT5

I bought one of these over year ago. It is a very well made, quality machine. It is light weight, but robust. It is easy to use and the battery lasts quite well. For trimming slightly longer areas of grass, or where access for a mower is difficult, it works well. However when trimming grass along raised edges and round rocks and other hard items, I was disappointed to find that the plastic blades break very easily. I would have expected them to simply pivot around the object and carry on, but instead they snap and have to be changed. While new blades are not very expensive, it is inconvenient to always have to carry spares (plus the broken bits) and keep stopping to change them.
I am looking to replace my Gtech with a suitable nylon line trimmer for my lawn edges.
I now carry the Gtech in my caravan, for trimming round it when we are away.
I also own a powerful, Stihl petrol brushcutter, but that is too big and noisy for home use.