Carry your RX, note from doctor might be a good ideal, your interferon is the only thing that needs refrigerated so a small container, (at the time scherring plough would furnish one that had a strap on it) and a frozen ice pack.
Also check with the airlines as they should have no problem storing it in their frig. during flight....... Enjoy yourself.
I did a lot of international travel during tx and had no problems. For a long flight I would pack it with one of the frozen thingies that came with every shipment. At security I would tell TSA that I was carrying injectable meds and syringes with a cold pack. They were real good about it. I always carried copies of my prescriptions but nobody ever asked for one.
When returning to the US one time I had to ask for a wheelchair to assist me off the flight because my hgb was low and I was wiped out from travel. They came and got me, picked up my bags and took me to the front of the lines for immigration and customs. That was really great because I don't think I could have stood in those long lines or carried my own bags.
Have a good time in the UK.
Oh wow that's great! I love to travel and want to visit my friend. Thank you both for the answers. Very useful information and I am glad to hear TSA understands these things.