In the 2001 shutdown of JET the septum, which separates the inner and outer divertor in the JET Mk-II gas box divertor, was removed and replaced by a simple protection plate. This enables a path of the neutrals from the inner to the outer divertor and thus a comparison of a closed and open divertor conguration. It is thought that asymmetries in the detachment process are influenced by the presence of the septum. Following septum removal, an experimental L-mode density limit session has been performed for comparison with a previous identical experiment with septum in place. The fuelling location was varied: inner/outer divertor and main chamber. Complementary experiments have also been performed to investigate the influence of the inner wall clearance on the L-mode density limit. The final density limit can significantly depend on the distance to the last closed flux surface to the inner wall.