Difficult access. Difficult highways issues.
Depends, surely, on exactly what is for sale. Assuming the store front comes with the yard, then there would be room for a modest Express type store, with room left over for more parking than the average one has.
If there is (relatively speaking) plenty of parking space, then I can't see there being a highways issue. Being located between two sets of traffic lights would give natural breaks in the traffic for people to enter and exit the car park without causing major issues (Yates' garage doesn't ever cause a traffic snarl up with cars constantly entering or leaving the forecourt).