Hi Hun,
I wonder if the clocks changing was just co-incidence and maybe you're looking at UT turning into OT, often the way.
Is she low/average or high sleep needs
Is there anything development going on right now which could be in the mix
Any disruption in the family/home life situation
At this age DS was on a 1.5 average nap with a 13 hour day.
In the first instance I agree that maybe early bed time or super early bed time could be the way to go in order to get a spring board for catching up, this was our saviour at that age. Does she tend to tack sleep on
Once caught up, as a first port of call I would try for a 13 hour day and leave the nap length and time alone.
(HUGS) Sweetie.
Let me know your thoughts.x.