It's quite easy really but my problem is that I can never ever plan ahead so when I decided to work this heart with two colours and I got to SR13 I hit the brick wall!!!  I HATE wasting precious HDT thread and as one of the colours I was using was an HDT I simply HAD to work out how to progress this idea.  
Now I'm SURE this isn't a new idea and I MUST'VE seen it somewhere before but as my memory is so poor I can't remember where.  So, this is what I did.  
First of all I worked the ring (13) as usual but hiding the chain thread inside along with the main core thread.
Then I took the one thread (the one I wanted to show) back down to the base of the ring I was making and lock joined it.
Finally I worked back up the other side using the split chain technique.  Really not rocket science.  
Having gone through ALL that and drawing up a new technique page it was gently pointed out to me by dear Georgia that I could've done a chain to join to the last ring and to the half way point, followed by a join down to the base and then a split chain.  The Dora Young Knot DUH!!!  Ah, well, there's always two ways to do anything and I always find the hardest way!!! 
Actually I prefer this way as I got a more 'rounded' ring than I get with the DYK method.  Any comment on that?