When I recently started out on HF these two antennas seemed to be obvious
canditates given the dimensions of my rear garden. I started out with an L of
similar dimensions to those quoted by the OP, and later tried a doublet (close
to half G5RV ) with an open wire feeder which ran rings around the L.
Not a fair comparison by any means outside the context of my garden and given
that the radial system for the L was 4 wires on the ground no more than 25 feet
in length.
My next step is to try a doublet of twice the length with the excess wire at
each end being guyed in various directions as necessary .
Have any of you experience of this and particularly of optimising what will
probably be an assymetric assymetric antenna?

John
M1JTA