I've only recently fitted a new headlining, I was hoping to tie it all in but was not sure if I wanted the shark fin type (the more I saw photos of it the more I thought it was too large) since then I've found the following..
2015 model year Polo aerial, has a gloss black finish to the base, overall I reckon it looks pretty darn good, oh the thread on the antenna part is 5mm. I'll only be missing GPS which I'll need when I get the RNS510 but a GPS antenna in the dash is fine.
Part numbers for the AM/FM, DAB version as follows...
6C0 035 501A - aerial base
6C0 035 849A - rod-type aerial
I've ordered them via TPS, the base comes in at £37.55 + VAT