I've had a bit of a play and answered my own question:
The answer is "no". It may use WebDAV for the actual file sync. process, but there seems to be a bit of a Nextcloud specific handshake required first. I could maybe build an appropriate response to "nextcloud/status.php", but this seems like the start of a slippery maintenance slope that I don't want to go down.
Now that I have my Apache WebDAV server working, I'm looking into other options for Windows, WebDAV based, file sync. clients. Any suggestions appreciated.