Her accent seems natural to me as well, I mean she has always spoken English in that accent. And its actually very normal to pick the accent of people around you when you live in a certain country, I myself had never spoken fluent English until I went and lived in the UK for a year and started talking to my American-Canadian family members almost every week.. so now my English accent is a mixture of British/American.
I don't know why people here are always so obsessed with Ash and PC's accents 😕