Thank you Wim

I have in my household toolbox a good supply of a very agressive flux which
I often use as a final attempt to solder to some modern PL259 connectors.
I just tin the surface with the aid of agressive flux then clean it all up
before soldering normally. I think this and plumbers solder may work. When
the roll of ckicken wire is delivered I will try a test run.

As the ground mat will be of a lossy material I am hoping the large number
of effective rf paths in parallel will mean that losses will be reduced. My
present radial system is four insulated wires that run to drains at four
corners of the roof and the down inside the plastic drain pipes to ground
level. Approximately 16 metres each. There are a futher four radials which
onle go to the edge of the roof but are only about 4 metres long each. I
would lose these four short radials but keep the longer ones. The wire mesh
mat would be 6M by 7M and would be much better than those short radials. I
can solder a few radial wires from the base of the antenna to the mesh.
However if I solder each wire to the mesh at, say, 500mm intervals I could
end up with more galvanic corrosion particularly as the air is very salty in
Dover.

The weather is changing and I think I chose a bad time to start this :-(

Dick G4BBH