does anyone have any ideas on stopping the cables (vhf,wind speed etc) slapping around at anchor

Take them out. I am. Less wight aloft you know. Saved about 3 pounds taking everthing off the top including cables.
There is the one cable up to the spreader light though that you can't really do without if you care to be out after dark...

Have you tried very long cable ties at 2' or so intervals. The excess on the ties contacts the mast and doesn't snag anything, but keeps the cables from slapping.

There was a post on this previously. I went out and bought the biggest wire ties money could buy, installing 3 at each station about every 4 feet, bundling up my instrument and light wires. They posed so much resistance during the installation that I damaged my instrument cable and had to replace it. I have a spreader bar that combined with the internal halyards, snags everything.

Plan B involves encapsulating the wire bundle in foam pipe insulation. This adds little weight, and you can't hear the wires if they swing against the mast wall. Simple and it works.

Dyk Luben
#405 Dream Catcher