My advice is to avoid the First Class lounge in Terminal A, it is really not at all good.

If you are travelling from terminal A the VIP lounge is better - I just get my carrier to call them a couple of days before arrival/departure and they add you to the guest list: Telephone (01) 812 52 05.

Failing that, I use the BA Executive Club or LH Senator lounges (even if travelling on SR) as I think both of them are superior to the SR First Lounge - infact Lounge may not be the right word!

Nick