Hi Rog, I ended up buying a Chester 20V mill in the end as Warco could only supply me with an imperial mill, WM14 or WM16. I was originally planning on getting the WM14 due to it's size, but then realised that I could fit the larger WM16 but went for the the Chester 20V as it was very similar and available.
As regards the DRO, I ordered mine through Chester, but it was sent to me from Machine DRO, so it is something that I still have to fit, but as I have fitted one previously from them to my lathe, I don't expect any problems. As far as I could see, the Warco one fitted to the WM16 is pretty much a standard optical DRO, whereas the factory fitted one fitted to the WM14 is non standard and incompatable with with other DRO's if you wanted to upgrade in the future.
When I spoke to Warco about the DRO, they could have supplied a standard DRO for the WM14 and fitted it for £200 if I wanted.
I would have probably bought a Warco mill if it had been available.
Hopefully my experience will help you with what you want to do, but if you have any further questions, please ask.
Keith