A Triton with your 1.4 Octavia would be good. I have the 1.5 version of your engine with same 150bhp output in my Audi A3 and I'm pleased with how it tows my 1200kg Triton.
A Troll should also be within limits as it would be no more than 1200kg. With two teenagers and related gear I really would advise you stick out for a 1200kg van be it a Triton or a Troll.
General adivice, ask for 13 pin electrics and a vehicle specific wiring harness. Also check that it will supply power for fridge and battery charging as these are usually an extra.
Having to travel miles to view/buy is unfortunately fairly normal. When living in Essex I drove to Berkshire for 1st Eriba, Belgium for 2nd, Leicester for 3rd and Nottingham for 4th.
Colin