Yeah, hugs from me too. It must be really difficult - your ponies are lovely and well worth what you are asking IMHO. I hope you manage to get some buyers soon who will appreciate them. But I can understand why buyers are thin on the ground. I wouldn't buy a pony just now as I would be afraid that I'd have to give it up and not by choice, if something went wrong.
I've never worked out how much Smokey costs me to keep - when he was in livery, I calculated it cost about £3000 a year. Now it's much less, partly because I only have him insured third party, fire and theft, so if the vet suggests taking him to the vet college, I'm afraid he's hound food - and partly because he's on our grass and that's "free".
The Highland Pony Society has a for sale board and have you tried "Native Pony" magazine?