Well, after a couple of attempts to get an update out of D-Link, they finally responded and said they can't replicate the problem on their router (which I already knew a month ago), so they are saying that the problem must be my router.
So they have agreed to supply me another dir655 -if I can find the invoice. This will make #5 in 4 years of the same model. Unfortunately it will take around 3 weeks to get the new router, so unless I buy a new router, I'll be offline for three weeks.
I turned off autoscan some time ago. It didn't make any difference. I did some checking, there are typically 2, sometimes 3, wireless networks in range oy house. Either way, the router still disconnects when wireless is enabled.
I personally found it interesting that the D-Link guy didn't say anything about the Austoscan feature; It was enabled on the version of the configuration file I sent him. Would it be unreasonable of me to be skeptical of his expertise? (That's rhetorical).