Line Chart - Changing series colours

I have a line graph with 2 series on but am unable to change the line colours away from the default blue, light blue.
Is there a simple way to change so series 1 is red and series 2 is green on the same graph?

You can use the action DataPoint_Init to specify a custom color for your data points. Color is one of the input parameters of that action which can have a value as "Blue" or "0000ff" (or rgb if I'm not wrong...)

That action gives as output a sctructure record of "DataPoint" type
DataPoint_Init color changes the colour of the data point but not the line itself.  For instance if I change the color setting to "Red", I get a blue line with Red data points whereas im looking to make the line red.
I can't say if this is the best approach, but you can achieve that by editing your style sheet.
Just use the class Chart_Color1, Chart_Color2 and so on. Eg: .Chart_Color1 {color: green;}

Hope this helps

Tiago, that has worked perfectly thanks.  I assume this can be applied for as many different series as are on the graph (ie up to Chart_Color5 if 5 series)?  Is there a different convention if more than one graph on the screen?
It can go up to 10 series. Unfortunately, this approach applies to all charts, not a specific one or group.
It kind of works as being the default setting for your app charts. 
I don't know much of HighCharts, but what I know is that to format a data series you use the structure AdvancedDataSeriesFormat, where you have two attributes: DataSeriesName and DataSeriesJSON.

You can assign your values to these attributes using the assign widget. Something like:
AdvancedDataSeriesFormat.AdvancedDataSeriesFormat.DataSeriesName = "Company XYZ"
AdvancedDataSeriesFormat.AdvancedDataSeriesFormat.DataSeriesJSON = "color: 'Green'"