Alpine, at least in Italy, markets 2 splitters for the VW Golf 6 and 7. The part numbers are KAE-DAB1G6 and KAE-DAB1G7.
Both use a Calearo splitter 7562029 which I can't find on the Calearo site. The VW antenna adaptor would probably not be required but you would still need some form of cable adaptor.
Instructions can be downloaded here.
Whether or not the cable from the active splitter to the radio is useful would depend on the configuration of the cable input on the radio.
This led me to find the Calearo AM-FM/DAB-DAB+ ACTIVE SPLITTER - P/N 7561004https://www.calearo.com/en/products/antennas/am-fm-dab-dab-active-splitter-7561004
Data sheet here.
You would still need the correct cables to connect the radio to the splitter and the input from the FM antenna. https://www.calearo.com/en/products/antennas-adapters
There are a couple of Re-sellers in the UK. http://antenna-products.com/http://www.celsusgroup.eu/