Chris Hogg formulated the question :
I rather thought the same. A quick search for diagrams of B&D
strimmers showed the motor to be in the head, not in the handle, so I
thought that perhaps the OP had a different model to the ones I saw in
the diagrams.

I have never seen an electric one, other that with the motor at the
ground and cutter spool on the end of the motor shaft.

Some other makes do seem to have flexible drive shafts.

The petrol models have the motor at the top, driving the head via a
flexible drive rod.