Do you think that deep down Sheila had a grudging respect for her mother, despite all the trials and tribulations both of them endured?
Steve, I think Sheila's relationship with June would have been hugely complex. Children love their parents unconditionally -rather like puppies and kittens love their owners. The love shared by parent and child is the only time they will experience unconditional love. I have the feeling that this wasn't the sort of love June held for Sheila as she continued to mature and stray further from the path June had prescribed for her, and I have no doubt that it left her feeling she she'd never please June.
It's possible that Sheila always felt conflicted between doing what June wanted -to gain her love- and following a path more suited to who she was. There may also have been, factored into this unhealthy mix, gratitude to June, on Sheila's part, for 'rescuing' her. Added to that would be guilt for not being able to be the daughter June wanted her to be, compounded by all the material benefits which continued to be heaped on her.
Children who have been made to feel unworthy, generally don't feel anger towards those responsible for that feeling, anger being the prerogative of the deserving. Having failed at so much, it's unlikely that Sheila would have felt deserving. It's because of this that I believe she never stopped craving, and trying to gain, June's approval.