I've read several articles about Thatcher's policies, and i've learnt about the fact that she instaured a society of personnal ambitions and really made a property owning democracy. I understand that she made a transition between and industrial economy which revolves around steel and coal to a service economy, but I can't seem to find anything more about how she influenced today's British society.
Kind of impossible to answer because although you're technically outside the twenty year period rule any decent answer would have to focus on stuff right up until the present day. Even then it is a difficult question from a historical point of view because it will probably be at least another few decades until enough studies, academic arguments, etc have formed some kind of valid consensus.
It is also a very political question which means even well sourced answers will have wildly different interpretations of the impact she had. Not just in terms of the differing arguments within British politics but also in terms of historical theory, questions like "was Thatcher a driving force for change, a catalyst for change or in herself irrelevant and just the manifestation of the socio-economic pressures and climate in Britain at the time".
It's tough enough answering your question about someone like Attlee, who we have another 30 years of retrospective on.
The best thing to do is to just look into her policies and time as PM basically, and then draw your own conclusions. I personally have some theories and ideas about Thatcher's impact but I would be hesitant of presenting them as historical facts.