Did LHR - DUB - JFK return in September, & was really impressed.
When you get to Dublin, head straight for the lounge, do not be tempted to try & do USPC first, once you have done it you can not go back to the lounge.
You will be told when to head to USPC when you check in to the lounge.
When boarding, it's not always obvious that there is a separate line for business class, but there will be, so do not be shy about using it.
Mrs ABZ1C & myself, reserved seats 2A & C on the way out & 1A & C on the way back, row 1 was great coming back because you do get a little more leg room if you plan to sleep.
As for the service, we found it excellent, the food was as good as it can be on a plane & there was plenty of it, the crew on both legs were lovely & really chatty & friendly when they realised we were on holiday.
On your way back you are allowed to use the lounge at Dublin before your flight back to the UK, just show your Orlando - DUB boarding cards & let the lounge guardians know that your on the Manchester flight.
I used the shower facilities on the first floor to freshen up, you will probably need to ask them to unlock one of the rooms for you.
The room I had was spotless with an array of clean fluffy towels & other bits & pieces.
We were so impressed with the business class product that we have decided to book for Orlando next year.
Enjoy your flight.