Another Newbie

[Chris J]

There are precision nozzles available for the better brands of plasma cutters, however it all depends on how much you want to spend.
Hypertherm is one of the top end brands that I can think of right now that I think does them.

The minute someone says it depends on how much you want to spend my blood chills a bit

I guess I was hoping to spend £1k maybe a bit more, not including a pc, so not a huge budget.

[m_c]

The minute someone says it depends on how much you want to spend my blood chills a bit

I think it has that effect on most people!
If only I could match those 6 numbers...

I guess I was hoping to spend £1k maybe a bit more, not including a pc, so not a huge budget.

As Ian's highlighted HiDef plasma is out of the budget.
I know normal plasma has a cut width of 2-3mm, and would be fine for doing the main outline cutting, so it may be worth considering a router/plasma hybrid. The two processes do have opposing requirements for cnc, but given your requirements, and with some careful design, should be doable.
Under typical use, a plasma table requires lots of speed with little torque and not very tight tolerances (when you've got something cutting +-0.5mm/trailing behind the torch position, tolerances/backlash requirements aren't that high), whereas a router table needs more torque with less speed but tighter tolerances.
However, given the size of cutters you need, torque won't have to be much for the router, and with the reasonable price of ballscrews, a good compromise of torque, speed, and tolerances should be doable, and combined with a lower power plasma cutter you shouldn't need crazy high cutting speeds.