Ah ha ha ha. Sorry, but I couldn't resist the cynical laugh.
I worked part time - under a flexible working agreement - in a Magic Circle firm until recently. My department were great, initially, at walking the walk and talking the talk IYSWIM. Flexible working arrangements were granted to a number of fee earners (senior associates; the only junior associate who applied was turned down) as well as to PSLs and secretaries. After a time, they realised that too many people were applying for flexible working (almost every mat leave returnee - and there were a lot). Consequently they decided that the only flexible working arrangement they would permit was one of 4 days
and, worse, they even put pressure on people on existing flexible working arrangements to increase their days to 4.
Quite apart from my firm's interesting interpretation of the regulations, from the fee earners' perspectives, yes, they got their 1 or 2 days at home each week and/or got to leave the office at 5 sharp but were still expected to be available by BB and email in the evenings and, on occasion, on non-working days. Also, it goes without saying that although they were only being paid for e.g. 4 days' work, there was no appreciable scaling back of work that the firm expected from that person. Oh yes, and, for a time, anyone on a fixed hours arrangement, had an additional 20% knocked off their salary.
Re career aspirations, I don't think people on flexible working were expected to give up on them but they were expected to be content with e.g. being made Counsel rather than Partner. I suspect that anyone who wanted to push along the partnership track would have been expected to return to full time working.
And really, this was a department that tried - it really did - to accommodate the wishes of a fair number of women (no men applied). Unfortunately, the way it went about it, at least at times, generated a certain amount of resentment and upset.
And I have to say, given the business model to which the firm as a whole adheres to, I don't really know how my department could have handled it differently (apart from its unlawful push back on the existing arrangements, that is). Will be very interested to see the Law Soc's proposal although am just a touch sceptical that firms will pay much attention to them.
Sorry for the essay!