The truth about Leanne Battersby's real mum

Comments left on this blog post have proved intriguing as to the truth behind Leanne Battersby's real mum and I thought it deserved a blog post all of its own.  And so, with full credit to http://www.corrie.net/ let's see what we can uncover!

If newcomer Stella, played by Michelle Collins, turns out to be Leanne's real mum, as rumoured, this means she obviously had a relationship with Leanne's dad, Les Battersby.  In which case, the description that we've been given of Stella as "strong, feisty and fun" can be stretched to include "a bit desperate". 

We also  know for certain that Les has fathered a son, Greg Kelly, from a relationship with Moira Wood (nee Kelly) before he met and married Janice Battersby.  But when did Les meet Leanne's mum, this Stella one, if the rumours turn out to be true? 

So what do we know about Leanne's real mum and what's been said about her in the past - can anyone recall?