The most essential element for me in all this change is actually a friend of mine who we joke is OCD about cleaning who got me started and who is full of amazing ideas - she helps me realise my vision. She is the action/do-er to my creative but procrastinating mind. XP did lots of moaning but nothing constructive. I couldn't have done it on my own especially working FT out of the home and being a single parent with very little time in the home alone.
My Mum is a classic hoarder and I have amazing ability to just 'not see' stuff - I think many of us do. And so it builds up. But my OCD friend got me going - initially by tackling my kitchen - Istarted a thread about it and then the "minimalists" got me over to an earlier version of this thread. 
I got so much inspiration from these threads - I'd always been terrified of the word minimalist. But I've learned so much, about myself and about my life and about change. Now I read minimalist blogs etc and keep the inspiration flowing. Quite simply it makes sense - it will be with me for life now.
After having help and support from ODCF, the most important bits for me were:
Break it into chunks - I do most big jobs every 2nd weekend when DC are with XP (for the first 5 months he just did Sundays - so I did it then)
Give yourself time off too - it's been about 7 months so far - still a way to go (though most decluttering is done I can see more stuff will go), but I don't do it all the time now.
Get stuff out - I was one who had to give myself permission NOT to ebay and just donate to charity shop so its gone. I feel good someone else will get the ££. For me the time and space is much more valuable.
Realise its a process - stuff is still moving around the flat all the time. new furniture will accommodate some bits that are in a box ATM. But once all the new furniture etc is in place, if it doesn't have a home it doesn't have a home and needs to go. It don't matter how lovely wonderful and special something is - if you don't have a place in your home for it to live, it doesn't belong there.
It's been a huge change - not only in the flat, but after the breakup of a LTR it was so good to experience what I can achieve as part of a properly functioning team (with my lovely inspiring friend), as opposed to being dragged down by X moaning at me, blaming me, contributing to the problem but not prepared to work together to resolve it.
I can do it! In fact I AM doing it!
And the best bit of all, after all the extra space we have, is it really is true that the less you have the easier it is to clean!!!
Thanks for all the support and encouragement 
It's been actually life changing.