advice on software and machine required please.

[JAZZCNC]

im in the up to £6000 bracket . but would ideally like to spend up to £3000

Ok then with 3K you are ok, 6K better still. By the sounds of it your wanting a real milling machine, yes I know you put milling at the the start but lots do that when they mean gantry router.
Depending on the material size you want to cut then 3 to 5K will get you a pritty decent machine, if you want large cutting area then you better dig deeper.!

John S is the man really for these desktop milling machines so I suggest you give him shout or he may be along soon.!!

i have no experience with cnc or cam so does all the cam software automatically work out feed rates spindle speeds etc for the material and cutter used?

Well yes and no really, What happens is each tool has it's own set of cutting data which either you program manualy according to tool manufactures settings or your own personal preferences and is then assigned a tool number IE T1. You do this only ounce and it's stored in a tool table so when you choose that tool the program knows all it's cutting data and programs the G-code accordingly.
Some software will come with preset data for differant tool sizes but often the case you'll change this to suit your your own way of working and preference.