Reciprocating play dates

[Peleus]

Since September a few parents at my DC's school have had DC on play dates with their DC after school because of a personal difficulty I had at the time. Now that it is all sorted, we would love to reciprocate and offer play dates back. Not just because they looked after DC, but because we like them/their parents too, and would genuinely like to spend time with them.
My problem is that, despite trying to set playdates up more than once, everybody seems to be too busy. I get that, because their DCs have siblings too, and their mums go out to work. But how many times do I re-try, without seeming needy and desperate?

Just to clarify, I am trying to organise individual playdates, not a group thing.

Since my eldest moved out I find myself constantly cooking too much fuel as stuff tends to come in packs of 2 or 4 and there are 3 of us. Luckily DH takes packed lunches to work with him so I parcel up the left overs and stuff it in his bag for work.
This week he took left over casserole on Monday and a gammon steak on Tuesday. Tuesday night he came home and made himself egg mayo sandwiches for Wednesday. However I had two fajitas left over so I replaced his sandwiches with the fajitas. He didn’t realise until he got to work and then wasn’t happy saying I’d sent him to work with soggy old fajitas and all of his colleagues were laughing at them and calling him a pauper!! I told him not to be daft, they were only soggy because the salsa had soacked through the wraps over night. Yesterday I made duck legs and we had two left over so I stuck it in a box and put it in his bag. He’s just text me telling me he’s not eating it as it’s embarrassing and he’s going to chippy instead. AIBU trying to be resourceful?? Just don’t see the point in wasting stuff.

Are you offering a range of possible dates or one specific date? If the latter, I would try the former. If the former, I would leave it for a few weeks, then try again. Then I would leave it for a longer period and try once more. After that I’d give up!

I give a range of dates to I could do. If none are suitable I say that the dc would love to have the child over, is there a day that would be good? If no response to that I leave it.

I do what Stompy said. Proposing one specific day rarely works with schoolkids, but sometimes it takes a while to get from vague oh-we'd-love-to-have-a-playdate talk to actually finding a mutually suitable time.

If someone showed absolutely no interest in sorting out a date and always gave a blanket 'we're too busy' response, even when you're asking them to suggest convenient times, then I'd drop it.