The owner of the pub he talked to on his way to the peak said he spoke british english with no accent.
According to news the medicine bottle found with the body was written in both english and arabic (
http://www.oldham-chronicle.co.uk/n...dlines/96442/mystery-man-hunt-turns-to-ulster). So the medicine may have been prescribed in an arabic country.
It is very possible that he was not reported missing or identified until now, because he lives abroad in an arabic speaking country and was just visiting. I think police should check recent flights from those countries to the UK and the passengers. And any airport CCTV.
He may have left his passport in an hotel he was staying in in London. That would explain that the body was found without ID.