From what I could see, she opened up the city salon, and made Mar the "manager" of the floor.
Sabrina then floated in and floated out, whenever she felt like it, not doing much work at all, as Mar was looking after the running of the salon.
Sabrina was "sick" a lot around this time, and out of work a lot. I think this might have something to do with the break up of her marriage at the time.
I'd say Mar got sick of doing all the hard work, while Sabrina took all the credit and the big bucks, lounging around at home for the most part.
Sabrina could get away with it, when she knew Mar was there looking after the salon, and keeping the money rolling in.
Since Mar left, you can see Sabrina is much more present in the salon now, and actually on the floor and doing hair.
When Mar was there, she was rarely on the floor, and had her client list closed, and wouldn't take on any new clients.
Now she is advertising for clients on Instagram, and actually has to do some hair dressing now, since Mar walked out.
I think since Mar and her husband have left her, she has actually had to grow up and become an adult.
Before Alan left, she didn't know how to boil an egg. The house was bare and never invested in.
Since he's gone she's turned in to Nigella Lawson, "seductive" eating to camera shots included.