Unless you're expecting a call from Russia or Kazakhstan (which are the two countries with numbers starting with 007 when dialled from the UK), you can safely ignore the calls.
Call centres ring several numbers at the same time and answer the first one that answers. The rest of the numbers go to the bottom of the list to be rung again in the future. So don't be in too much of a hurry to answer the phone especially at odd times when you are not expecting a call.