Sorry I don't know the name of the recommended engraver but you will see from my post that the heel bar engravings are definitely a no no. Got one done, as recommended by Brendan, in a trophy shop in Capel Street, which is opposite Lenehans. So far it is working out well. The inscription is quite plain which is fine for a dog disc. Some of the jewellers used to do ornate italic which was quite hard to read but a lot of them don't appear to do either repairs or inscriptions any longer.
Make sure to see a sample of their work before you let them start work on the frames. Not too sure about this but as the frames are silver plated cleaning might wear away at the inscription also.