I used to use the LGW -DUB service regularly as it was convenient and offered reasonably priced J (I seem to remember a CE return was about £200).
Given that I only fly J, there is nothing at that price point now. In fact I am not sure that there is any direct J at all any more. BMI used to offer it (but for about £700), but don't seem to anymore. Hence I never go to Ireland now.