Actually I do speak Polish guys so if you wish I could give them a call and ask if they sell adapter on its own. Although I think that I found it on their website:
http://www.sklep.milecki.com.pl/adap...raz-p-550.html
It states the following:
Thule Adapter 9042 EuroClassic is bypassing the spare wheel. It allows installation boot EuroClassic 908 and 909 G5 and G6 928 and 929 to hook the car with a spare wheel on the back of duly reducing the boot capacity with one bike.
To compensate the reduction of luggage capacity, use following compensates snap-on Thule EuroClassic 9081:
http://www.sklep.milecki.com.pl/przy...az-p-2557.html
I hope above helps to solve the mystery. It doesn't say anything above delivery outside Poland however I can easily call them and ask if needed. For Poland if order is over 1000 zl or around £200 is for free so I am pretty sure delivery is negotiable.