1. Around ours for dinner and Sally whispers in Tom's ear and Tom doesn't react (this whispering happens numerous times and makes me so uneasy)
I would be disturbed by this, too, but not sure what you could do about it.
2. Booking a delivery slot at the height of the pandemic for their groceries when vulnerable people are struggling to get one. They live so close to a waitress and a Tesco and are not vulnerable.
Not your business, and how do you know they don't have a medical condition you're not aware of?
3. Not environmentally conscious at all. Not Recycling anything even thought they have every opportunity to and chucking excessive amounts of plastic and cardboard in the main trash. Around theirs for a party for Sally's birthday and at the end they just chuck all the left over food in the bin, plates of cake, sausage rolls, fruit, etc. No concern for food waste.
Have you mentioned this to them, eg a helpful, "Oh, did you know you can recycle X now?"?
4. No doing anything for my DP's birthday (beginning of March before lockdown) of my birthday (last week) despite me arranging cakes, cards, parties, and surprises for theirs (I know I can't expect but it is disappointing). We are also their only friends as they keep telling us and we all really enjoy hanging out every week without fail until the lockdown. They have been furloughed both of them so would have had lots of time to write me a card and have a cake delivered. (They are also very very wealthy with no children incase this is relevant)
They haven't reciprocated, so I would pull back a bit with the unsolicited gifts and parties.
But you don't actually seem all that compatible from what you've said, so what did you enjoy about hanging out?