Hi,
I was going to get some glasses engraved before my sister's wedding a few months back, and came across this guy's phone number in the Golden Pages: [broken link removed]
Was talking to him, and he said that as he does all the engraving by hand, he is better value if you're just doing a few items, or if each item will be different. He did mention that Dublin Crystal would work out cheaper if the engraving was something such as a photograph, or if you wanted to get a large number of items that were identical.
From what you said, it seems Dublin Crystal would suit, but I thought I'd mention this other person who I found, just in case that's more up your street.