I had a customer with one of these and it would judder at slow speeds. It seemed to be foaming in the reservoir. Tried the top up to 25mm above level as per Autodata.
Sometimes would be ok for a while then would foam and sometimes overflow.
Spoke to Peugeot and there is a modified pipe for this issue.
My customer declined the repair and sold car as it needed lots of repairs.
Might be worth a phone call.
Iain