I think I've got it! I made round, soft, pliable, buttery chapatis! Well, Big'Un still complained there wasn't enough butter, but she'd complain the butter didn't have enough butter...
I tried Anjum Anand's suggestion to leave the dough to rest for half an hour in a WARM place, covered. Most other books and things have said in fridge. I honestly don't know how my mum does it, I know she DOES keep made up "atta" (she calls the flour and the made up dough both "atta") in the fridge, but not sure if she lets it warm back up to to room temperature or not... Must ask her. Why do I only ever think of these things when she's halfway across the globe! Mind you, I do tend to cook Indian food more when she IS away for the winter. Partly, it's good warminig winter comfort food; partly, it's that I miss my mum, and Indian food reconnects me to her...
So I also found that the skwish and twist method helps. That is, once you roll the ball of dough, dust it in more atta, then before rolling out, use the palm of your hand to press down and twist - clockwise seems best. Then when you roll it out, the disk rotates and this eases the circularity.
It also eases the puffing up which is pretty essential too.
So the "tools" I use are - a chapati thali - wide flat bowl for making chapatis, given to me by my Sindhi grandmother when I got married.
Satilon Futura "tawa" - amazing stuff. Non-stick to the extreme. I scrub it with wire wool after the blokes don't wash it properly after I've made parathas and it comes up a dream, no scratches.
wooden rolling podium. - bought online for a few quid at spicesofindia.co.uk - fab store
thin Indian style rolling pin. Really seems to help the auto-rotating.
Weird mesh thing for puffing it on the flame.
I'm sure they all help a little, the rest is practice, and my family seems happy for me to practice!