Now I've got the right data set I'll start again.
Pretty rare for LTN RVR to go as low as 200m but last Friday there were consecutive readings of 225, 200 (both on 26), 200, 225 (both on 08), there being just the one runway given in those METARS. The lowest that day was 175m on 26 (again the only given runway) at 0220. Obviously it's worth trying to solve the problem but hardly a disaster for LTN if that should prove impossible.