Off-street parking is the baseline requirement — trailing a cable across a public footway is not permitted. Beyond that, installers look at the distance from the consumer unit to the parking space, the available spare capacity, and the condition of the earthing arrangement.
Solar and charger installations are notified to the local network operator. Small domestic systems are usually handled under a connect-and-notify process, but constrained parts of the network can require prior approval, which adds time.
Get the roof survey and the electrical survey done together where possible. Combining them avoids a second visit and gives you a single realistic date for the whole system.