It was 2m APRS (144.390) Could have been anything I guess. I was doing antenna work on the vertical mast, and temporarily put the APRS radio on a 2M7 Yagi pointed east for a few nights. That may have been a contributor!
That's quite a distance for 2m! I don' t know how often terrestrial 2m makes it across the pond. I checked the moon position in the off chance it could have traveled via EME but the moon was "down" for your location. That is pretty impressive!
Terrestrial (verified) contact on 2 Meters from North America to Europe still eludes us, but there IS an award associated with it. Many have tried, but none, so far, have succeeded. Via EME, or satellite, not that rare. When the late summer duct opens, it's not uncommon for CA operators to work Hawai'ian stations, CW or SSB, even FM on 2 Meters; the duct often propagates signals up through 10,000 MHz. But that is less than the current "claim."