Diversion Airports

Sorry if this has been asked and answered before, but earlier today and again less than an hour ago, I watched 2 flights on flightradar that had declared a 7700 emergency.

First was a Delta A330 out of Amsterdam, that was flying up the North sea, it was on a level Just South of Edinburgh, when it did a u-turn and returned back to Amsterdam.

Edinburgh regularly handles A330s I believe and Glasgow has regular flights by Delta, Aberdeen would also be a closer option without having to turn around.

The second one is is a Flybe Dash 8 from London to Edinburgh, that squawked 7700 over Windemere. that turned around and went South to Manchester. I”d have thought Leeds/Bradford would have been closer.

I realise that for long haul there have to be diversion airports available especially on pan-oceanic flights, but surely for the Delta flight that hadn’t reached the open ocean, then any where capable handling the aircraft and the emergency would do?
And for short city jumpers why double back when there are closer airports that take that type and airline on a scheduled basis?