Whilst it's great to see NSCers helping out other NSCers in this way, I just want to remind people that a ticket purchaser remains responsible for their guests and their behaviour.
I didn't necessarily mean "dodgy avenues". A little bit research may be required, but my understanding was that Club Wembley ticket holders, who are the bulk of the middle tier, are able to legitimately sell/transfer their tickets for specific events. DYOR etc.
There will be a lot of level 2 seats available from avenues other than the club, if you are willing to pay. You'll then almost certainly be able to find two empty seats and actually sit together.