I love that you are buying the real deal too - I genuinely don't get the point of the fake stuff. You could save another few months and not have that niggling feeling that something isn't the real deal - plus the real part is worth more if you want to resell.
It's like people who crap on Apple products for being more expensive but fail to mention that resale on Apple products is vastly superior to anything Sony/Samsung etc
I still think a J's Racing wing would look great on yours. They're as close to OEM as an alternative can be since they do supply aero parts to HPD, specifically the hoods for their TCR Civic racecars. The wing is made of carbon fiber and it's adjustable.
Technically the Apple comparison is true. But I think Mugen is definitely above them since most of their parts, including the rear wings, are at least made in an ethical country.
I'm surprised you still go through Mugen retailers in the UK that just deny your access to parts you're willing to pay for, rather than the guy I know who got me the S660 aero illumination kit no questions asked.