Rough grass strimmer

Im surprised the Stihl isn't up to the job GG, I know they're highly rated by most.  Was it the FSE 31 ?

I have an very old B&Q corded one I use for tiding up when I don't want to the get the petrol one out and fight with it, the line is much thinner than the petrol and I find it slices grass better than the thicker line which pushes the thinner stuff down.

I think the FSE 31 is 1.6mm line might be worth trying 1.2mm if you can get it.

Gurgle tells me the line is 2.0mm on those  Probably very good for knocking down a rough patch full of tall grass and weeds but a bit thick for trimming around the veg beds.  Not sure if you can get smaller line for them ?  Been and Queued do a dirt cheap strimmer (about £12) which would probably be cheaper than a new line for the FSE81  It will probably come with the thinnest, nastiest line available but it would give you the chance to test the theory.