[1] See regulations 24 and 26 of the PTR regulations (response) and (response to an investigation under regulation 23 where it is decided that there is or there may be a qualifying liability).
[1] Gweler rheoliadau 24 a 26 o’r rheoliadau Gweithio i Wella (ymateb) a (ymateb i ymchwiliad o dan reoliad 23 pan benderfynir bod, neu y gall fod, atebolrwydd cymwys).