Paper Interrail Pass - where is the pass number / number invalid......??

Hello - I have an Interrail Paper Pass - I’m trying to book Eurostar - via b-europe.com - I have got all the way to the end but keep getting invalid Passholder Number. 

Where is the Pass number on the current paper pass please? (on b-europe it says its top right of the pass - but this shows my passport number - 9 characters // on the paper pass on the bottom left is a Stock number 080xxx74 - 8 characters plus on the back of the pass there is E 8077974) - all options seem to say Invalid Passnumber.

Can someone help please?

Thanks