Vrs wagon coolant flush

My cars getting on a bit and I can't see any info in the log to say that it's ever had a coolant change, plus the coolant looked extremely orange in the pipes. 

I'm hoping to give it a flush out and clean, perhaps get some of those aluminium pipe joint kits I see dotted around fitted too while it's empty. 

My manual says I should be using g12+ lilac coolant. I'm led to believe that purple g13 is the newer version and is interchangeable, is that correct? 

Also, the coolant currently in my reservoir looks very red/ pink and nowhere near purple/ lilac, I'm assuming that's had red coolant in it because I don't think any amount of rust would turn purple or lilac liquid that colour. Does that pose any kind of problem?