Apparently this is quite a common problem, especially near the connector like mine? (don't seem to be able to upload pics but it's similar to the link) Old link, but still. https://www.cultofmac.com/128714/apple-introduces-magsafe-adapter-replacement-program/
The last update was 2016, but it seems to suggest you might be able to get it replaced even if out of warranty (mine's just a few months past) as they're pretty expensive. I'm away at the moment, but in the meantime I've wrapped the split with some rubber, will be that be okay for now? People say cover the split with insulating tape, but there are thin copper wires exposed, and if I put tape straight over them I fear they'll rip if the tape comes off, so I think my solution is better though I might be wrong.
Edited by techphobe, 09 August 2018 - 07:18 AM.