I am looking at the EGLL ILS DME Rwy 27R approach plates and I noticed that it does not have step downs for the LOC only approach like US plates do. so then how is a LOC approach flown? at 7.5 DME an altitude of 2500 is printed, then GS intercept at 1410 at 4.0 DME and then there is LOC 1080 at 3 DME and the MDA is 420. So starting at 7.5 DME does that mean I can descend down to 1410, or 1080? AND when can I descend to 420 at 3.0 DME? The approach gives a LOC descent gradient of 5.2% and with a ground speed of 140 that's 755 fpm. In the US we can use that for a continous descent approach (CDA) which actually raises the MDA by 75 feet. But if I want to to get the the MDA of 420 without using a CDA, how is that done with this chart?