Thank you for the suggestions of KLM & Alitalia. I did look at these but as far as I can tell neither will credit miles for the Virgin & Hawaiian airline flights I am about to take. I haven’t been East since 2008 and my EU travel is sporadic at best so I don’t they are suitable for my circumstances.
It looks like a straight choice between Delta & Virgin at the moment unless someone can recommend another option. Since Delta is now a spend based reward system, my instinct is to go with Virgin.