What does the TV scart on the avant do. it has the 3 at the top AV, Video Decoder etc. and then further down the back of the TV there is a TV socket on the left and the video decoder scart socket. What does the TV one do and can i plug a set top box in it?

The Tv and decoder socket you meen is from the internal videorecorder and and tv socket you should have a scart cable to video socket

higher up on tv set, else video doesn´t work

the video decoder is plugged in to the video decoder at the top. but there is one empty socket at the bottom that says TV what does it do?

CJM1:

the video decoder is plugged in to the video decoder at the top. but there is one empty socket at the bottom that says TV what does it do?

Even if that work..It's wrong ! 

The right connections are between tv socket on vcr and video socket on the upper connection panel

AV and Decoder on upper panel is for external sources

then you have decoder socket on vcr left and that should be empty (the video inside is a standard Philips vcr with that connection and are not used in b&o)