Taking @WestFm's advice, I've managed to communicate with my STM32 board (that looks a bit like a Maple Mini) i.e

But I can only get serial to work.
I have tried the 2 boot pin links in all positions and I although a USB device appears, regardless of Link settings, it just comes up as unknown device on Windows 7, and I tried using the DfuSe from ST's website and also the one that mrburnette posted, but neither seemed to recognize the USB device.
I have yet to try it on XP or Linux, so I guess there is a chance one of those may behave differently
Anyway. I did manage to connect to the board using a USB to serial connector which I normally use to program Arduino Pro Minis' , using the ST's "Flash Loader Demo"
However all I've done so far is to see if I could download, and unfortunately I have a driver issue with my USB to Serial which causes Windows to crash into blue screen sometimes, which us what happened using the Flash Loader.
So I guess my next step is probably to see if I can upload the Maple Mini bootloader onto my STM32 board.
So I'll post to the forum and update if I manage to do that
Edit.
Just uploaded Maple_mini_boot.bin to the board via serial, and the board is now reporting as Maple 003
Hardware ID's
USB\VID_1EAF&PID_0003&REV_0201
USB\VID_1EAF&PID_0003
The next step will be installing the Maple driver on W7. I better download and install the Maple IDE and see how things go.
Hopefully W7 will not be as much hassle as W7, but I imagine that there are similar driver signing issues :-(
Edit 2.
I have the same driver signing issues with W7. aarrggghhh.
Looks like the only way to load the driver is to reboot and temporarily disable driver signing, but its a pain to need to do this each time I reboot.
Also. The board I have, doesn't have the LED on the same pin as the maple board and also doesnt have 2 push buttons, it only has a reset button, but looking at the Maple mini schematic, its easy to wire another led and it looks like i can use the jump links as the push button, as long as I connect PB8 to the Boot0 link.
(Maple has the LED on PB1, it looks like the LED on my board is on PC13)
I'll need to wire up the LED otherwise I can't see it flashing during startup, to work out when to use the jump link to trigger the various USB configs required for the full setup.