I have a brill cover made to spec from specialisedcovers.com been a customer of Douglas for 16 years now he’s made me some lovely fits 
fleece lined shower proof elasticated some of his work …
Just to say this is an elasticated fabric with a soft fleece inner will not Rub in the wind the bottom of the cover has heavy duty elastic edge to it contours to the cars shape,… the reason the cover on the MX~5 picture looks much longer is that it was designed with a boot spoiler in mind the spoiler has yet to be fitted …
top my old RX~8 cover
Back end Of the MX~5 ND2
best place for a Deal is the NEC or NIA classic car show " when its Back "