Hi Stuart,
The electric sockets here are the dual prong 220V that is commonly found in Europe (See photo).
You certainly do NOT want to roam using UK mobile data unless you want to spend ungodly amounts of money on data. Instead, ask your mobile operator to network unlock your phone (even if it's temporary) and purchase a local SIM card when you arrive at the airport. It's €1. Or they may even give it to you for free since it won't work unless you recharge it. Just ask them to activate the €10 plan (both of the local operators have such a plan) which will give you about 5GB of data for a one-month period.
Have fun. And if you have any other questions just post them.
Angelo
Pending my arrival in Feb can I ask about what kind of electric sockets are used in Cape Verde?
I'm assuming they would be as most of EU but it would be nice to know for certain.
Also will my UK mobile data work over there or would it be best to purchase a CV sim from somewhere?
Thanks in advance
Stuart