iPhone/iPad: Cannot delete autofill address data

I cant seem to delete old autofill data from my ipone or ipad. I followed instructions on deleting addresses in Apple pay but they just reappear again. Also my phone is trying to fill in old data for my home address and has my new home address as my work address but I just can't find the root cause of this data. I can see from old threads that this has been an issue in the past but surely the issue can't be that difficult. Many thanks