Thanks. In that case, what's the cheapest way for me to get a reasonable amount of data (e.g. 30MB to 50MB per day) on an iPhone for 3 or 4 days?
A nano-SIM is €10, which includes €5 of credit. I don't want to add an additional €5 credit, as €10 is enough to pay for 3 or 4 days, otherwise it would be cheaper to pay roaming charges with my Orange UK SIM card.
500MB of 4G data costs €6, but I'm guessing I'd have to add another €5 of credit to pay for this, resulting in €4 wasted.