Thanks everyone for their help and advice.
I have done a fair amount of reading over the weekend and decided that I won't be using the the Nordstrand on my car, the paintwork is currently in fantastic condition so to risk ruining it with a rotary polisher with zero experience would be crazy.
That said, I am going to get a scrap door and give it a go as having the skill for the future I believe would be worth having.
I have also decided to invest in a DA polisher to make polishing and waxing easier so if anyone has advice as to which to go for - that would be great.
Thanks all again.
There are basically several options when it comes to a DA. The basic machine DAS6 is a generic polisher which is a good machine and is one of the cheapest options. There are more powerful versions such as the DAS6-Pro which has a more powerful motor. This is very useful as the basic machine can bog down under pressure and so the extra power reduces this. These machines have been around for many years and have stood the test of time. These machine can use different size backing plates i.e. 5" and 3". Smaller pads are great for intricate areas such as bumpers or door frames.
In the last few years, a variation of the DA has entered the market and there are the longer throw (orbit size) machines. I have not tried one of these machines but seem to have the advantage of quicker cutting and lower vibrations. These machines do seem to have become very popular with many people. The downside is they cannot be used with smaller pads.
Here is a review and description of a larger throw machine from Autogeeks. The machine they are looking at is a fancy and expensive model but lower price machines can be bought easily in the UK.
I moved from a DA to a rotary as it seems I am one of the unlucky ones who seem to be very sensitive to the vibrations of a standard DA. A rotary does not really vibrate and if I had the budget I would try one of the longer throw DA polishes which seems to have better vibration properties. For example this one ShineMate - EX605 Orbital Polisher Kit - Clean Your Car
Just to add to the options, you can now buy small DA machines eg Vertool 12e - Mini Dual Action Polisher - Clean Your Car
which I suspect are perfect for small areas and interior cleaning, however, these small machines are probably more of a additional polisher to a full sized one, rather than a stand alone polishers.
If you have a healthy budget then you are into the products of the professionals and will last many many years.