Don't get me wrong, I'm all for the Welsh language being preserved and also for the Welsh names to be documented.
If the names appear on an OS map then mountain rescue will be aware of them. I mean, ideally people would be able to use their phone with the OS app to give a map reference to the rescue team but seeing as it's usually the ill prepared that get into trouble then a way to narrow down a search is useful especially in challenging weather conditions.
Also having heard cousins repeatedly pronouncing Dolgellau as "doggyloo" even after I had explained what the real pronunciation was makes me sceptical that putting the Welsh names on a map which will be largely used by non-Welsh speakers would be helpful.
Udderly superb.