Share your experience!
When you 1st had it repaired did you receive any paperwork stating the phone had been replaced? if not then you would need to contact Xperia care as without proof EE has no evidence that the phone you are handing in is the same phone which has warranty - For all they know it's a friends phone and you are trying to have it repaired on the side or you are trying to pull a fast one
They should or I'd hope so because if not then for all you know a staff member has pulled a fast one which in reality is theft