Well i live in thick clay soil and quite the opposite z5 climate but others with good knowledge on sandy oceanside will chime in you definitely are in more of a maritime climate like people in the PNW or nova scotia area.
Orangered is absolutely amazing but she usually needs some heat and wont take your cold. Zard, Hoyt Montrose (or just montrose) the harrow series harcot harogem should work good. Tlor tsiran is a z5 (or maybe z4?) hardy apricot for sure as i grow it in z5 denver colorado. Your apricots probably need a stone wall or something behind them to thrive and ripen properly with extra radiated heat or you could do a greenhouse like all of us here eventually are drawn too.
Gisela and krymsk have done well for me here, I would hope the nursery near you would be honest about what works and not like some of the scam online ones we have here in the states that sell you things they know they should not.
These guys in Seattle and on the Coast would have a better idea on what ripens well in those temperatures without any microclimate