I posted this up thread but the BOI credit card below gives the same lounge access, priority security and priority boarding as platinum and concierge. Its also looks like this card will be avios earning in the future as per the Aerclub link below. I am a bit worried that this feature of the card maybe removed but I note that the old Gold Circle logo has been replaced by a generic EI logo on the newer cards and with these features referenced on both BOI and AC web pages it is presumably here to stay for a little while. Depending on the earning rate tis may be the sweet spot on AC for me.
BOI master card
AerClub MasterCard lounge access