I you need to be under a doctor in the UK, I'd check again what the difference is between UK and US Heparin. I'm no expert here but was surprised that there was indeed a difference. From my reading, it seems to be the concentration, so if you're going to be under a doctor anyway who will be monitoring the levels you would be fine using the UK stuff (which seems to be the standard worldwide and what they used in the US until 2 yrs ago when they alone adopted the WHO standard).

Again I have no idea of the set-up in this situation but in the UK even when a doctor prescribes medicine, you actually collect it from a pharmacy. I can't imagine a doctor's surgery sitting on great stocks of Heparin for you (in your own words, a suitcase full...)