As I understand it, there is case law on the subject of 'loading' which deals with the interpretation as regards yellow lines, loading bays and exemptions from stopping restriction, as here.
The point is that 'loading' should be construed in the same way whenever it applies.
Here, among other matters it means that the load was such as to require a vehicle to transport it.This need varies depending upon whether the vehicle was engaged in a business or not.
So OP, the background pl.
Are you employed/self employed/ private DIYer, the vehicle is a goods vehicle or not, you go to the shop to buy or collect/deliver/return tools and equipment or what?
Over to you.