I have some Portugese Laurel that's about to flower - not sure if bees like it or not yet. Early bramble is flowering but doesn't give much nectar it seems.
I think you have quite a good advantage Nigel in the timing of forage for your bees. We are well into the June gap now here. Everything flowers way too early and its too windy and cold to gather. All the species you mentioned are well finished and away to seed now. Today is 10c, pouring down and blowing a hoolie from the North.
So answer to the question..... NOTHING