I think that was true for Jeremy (foreign trips, car replacement) but not of Sheila. I don't see her as materialistic in the slightest. June's worry about the damp flat in Hampstead and her concern for the twins led her to buy the Maida Vale flat, not any prompting from her daughter.
I disagree in reference to Shelia in the early days Steve.
She had ambitions of being a top model.
She wanted the London life, it wouldn't have come cheap. And June and Nevill were paying for this. The Lucy Clayton school which June paid for, who financed the Japan airflight ticket? Who financed the nights out? Shelia was between jobs,Colin was on an art grant, the bank of Nevill and June !
I believe Shelia was monetary based as much as Jeremy was. Perhaps not as much as her problems got worse. But certainly was at a time.