I have recently changed my A3 for an A4 so I have a Travall Dog Guard and Boot Liner for sale bought around 10 months ago. They are both designed specifically for the A3 Sportback with the guard fixing in place between the seat. The Boot liner is rubber with small lip to trap any spills etc. They can both be taken in and out in seconds.
More info here: http://www.travall.co.uk/2004-2012-5...ort-pack-p4119
I bought them for £125 so I’d be looking for £80 collected from me (close to Stansted Airport) or I’ll meet within 20 miles.