I saw a neat little nano clone with a screw shield built in !
it uses a ch340 usb chip
does this mean that the windows IDe will not recognise it as an arduino ?
will it be a problem to use one of these clones ?
The IDE does not care as long as it has the standard Nano bootloader. You will need to install the ch340 drivers if you must use Windoze (Linux would just work without comment 
).
This looks like an excellent board for twice the price of a common Nano clone.