Lidl have plastic motorbike covers in that are perfect for a small lathe. I have one on my Myford ML7 but there is plenty of room for a larger lathe.
https://www.lidl-ni.co.uk/en/p/winter-car-accessories/motorbike-cover/p36748
It has been successful in helping to stop the lathe rusting in my damp workshop. I know it works because someone (not me) was being nosy & was looking at my lathe but didn't replace the cover properly.
The exposed part of the lathe had some surface rust by the time I noticed the cover was off! 
https://www.lidl-ni.co.uk/en/p/winter-car-accessories/motorbike-cover/p36748
It has been successful in helping to stop the lathe rusting in my damp workshop. I know it works because someone (not me) was being nosy & was looking at my lathe but didn't replace the cover properly.

