Leeds went self dispatch in the late 1990s for a period, where we had to plunge out. A number of incidents took place, mostly involving trains waiting at the mid-platform signals and finally it was judged simply far to dangerous to self dispatch as staff were occasionally focussing on the farthest end signal (eg 12A / D) and not their own. That said, on the odd occasions when staff were missing during the night, on agreement with the Leeds Panel signaller and his boss' authority I have seen the occasional train self-dispatched over the years as a last resort.
First Transpennine Express successfully managed in 2015 to implement self dispatch at Manchester Airport after initially trying and failing in 2009. Initially, many signals were trackside, and out of view of conductors - the 'OFF' indicators were sited behind the road-bridge for some time too making for a quite risky dispatch. Following fulll resignalling with the extra platforms it was passed off as safe. One place I heard they did fail was Liverpool Lime Street, where it was initially approved following a (company) risk assessment then later overturned when ORR reviewed that assessment. Lime Street is a wiggly station with exceptionally poor signal & off indicator siting - and a skee-wif gantry of signals off the end that could relate to any platform.