No you cant access the Anna Livia lounge as this is in another area and you cant go from area A to area B or C without first going through arrivals and then upstairs and back through security. It depends on how long you have there. It may not take that long to do maybe 20 mins and once in are B or C its easy enough to get to A gates again . Its a funny setup and a pain .
Now thats the official route but if youve got the balls you could try get through the NO entry signs!! A few months ago I thought my Aer Lingus flight was going from the A gates and proceeded there. When I got to A gates I realised I had made a mistake and the flight was boarding from the B gates!!! I just thought to hell with it and ducked under the barrier as no one was there and I wasnt about to miss my flight !!!!