I was not really happy with the scale height so I removed it from the old base and added and extra 1cm lift to make it look better with 25mm figs.
The lift up was covered with scribed cardboard and some Wills plastic embossed stone sheet I had spare, the original 0.5 cm lift up was disguised with some Wills brick strip. I then added a new porch structure. I added porch doorway from plastic strip and cardboard, and a cardboard roof. Repairs were also made to the bases of the buttresses.