Since I live in the U.S., I'm not familiar with the cultivar Bramley, but here, cork spot and/or bitter pit sounds a lot like what your are describing. The larger fruited trees here (bigger apples, that is) are more susceptible. My guess is that you had an overly dry or extra wet spring season. Lack of calcium is the culprit in the two disorders I've mentioned and since almost all calcium uptake in apple trees occurs within the month following bloom the moisture content of the soil should be even and slightly on the damp but not water standing in puddles, wet side. Fortunately, the condition doesn't really have anything to do with the overall health of your tree... Good luck next season!