Letter to Wansteadium: Let me let

Wansteadium reader Mehvish writes:

Dear Wansteadium,
I was wondering if you could help me. A number of shops on the High St have closed down or are closing down, sadly. However more often than not no sign goes up to say they are available for rent – a new business just pops up! How do the new vendors manage to get their hands on the premises- who is in charge? I am interested in renting a shop but always seem to be too late!

Answers welcome via Comments below.