The tuesday morning swim is smaller, just two lanes and caters for stronger swimmers OK but subscription is not restricted. If your swimming is not reasonably strong (comfortable at 1:45/100 or faster at a guess) you will find yourself uncomfortable if you struggle with pace. Today was the first tuesday swim of a new 8 week block so you won't be able to join this group for a while as both lanes are fully subscribed.
If you don't swim with the club yet then there are swim options available still on Monday or Thursday nights in Wicklow and Greystones respectively. Come down to Shoreline Leisure in Gryestones on Thursday if you can and talk to the coaches, chat to other members and see if you can use either of these options for the moment. Both of these swim sessions are showing as open on the EPP online payment system, you will find a link labelled "Pay Now" on the club home page.