It is nice to get a SIM card shipped to your house before your trip. I did it twice, 2016 and 2017. I ordered a SIM card for Germany. In 2016 Prepaidzero sent me the Sim card with a German tel. number in advance and I could inform my contacts of my number.
In 2017 I ordered the same, but was not given the number in advance. I had to activate it in Germany and I received my tel. number. To my surprise it was a UK number. I did not like it because my contacts had to dial as if they call the UK. I could call, but rarely got a phone call. Firstly it was expensive for my contacts and unless they have a plan to call the UK, they could not call you. No reason was given upon my inquiry why this was so. For me: NO MORE PREPAIDZERO.
The advance shipping of a Sim card to your house.
Improvements or suggestions
Do not give out UK cell numbers to those who do not travel to the UK.