Can I just load it over my 066 version, I just bought the licence will that be OK? Will I loose any settings?

Best to save your xml, plugins folder, brains folder and licence file in a safe location then if anything does go wrong you can place them back. Its unlikely anything will go wrong but you never know
Oh and yes just install over the top of the current version.
Hood

OK, installed 057 version all looks good except for my pop out jog screen the jog cycle step and mode led's don't come on, can't select step amounts but can type them in, jog and step work but no led.
I will try and install it again

That may be DSMPC issue, not sure. It all depends how the plugin is working things.
Hood

Works on the 066 version. Is it me or what... can't seem to get any consistency, wish I had a machine just running Mach3 then would know for sure.

Ah ok well it should work fine then.
Hood