There is a side entrance through the gates where you could leave buggies, failing that (if it is not open) I am sure one of the kind SE23'ers could assist you into the building.

Unfortunately in my many years visiting the school with a pram my access
was mainly through the kindness of strangers. I know of two friends going to the sale today who both have twins = double buggys.

So something has to give. I will be there early today to help set up the stalls so I will raise this issue.