I'm in the far east and have recieved a letter back home for an ultrascan referral?

All of the places you visit will have access to such scans , but it will cost a lot of money and is not covered on any travel insurance . I think the request to go for a scan has been triggered by your previous symptoms and has come out automatically for a follow up review . If you have had some reurance from your doctor then perhaps whoever has opened this back home can explain to hospital and have the scan scheduled for when you get back . However if any symptoms show before then you probably should return home for the scan . Make enquiries as you go along at various countries medical establishments and see if/when they could do it and how much it would cost . Also how quickly do they give results and would they know what the scan was actually looking for