Hi mate, I use a polish and finish called Quixx - google it - comes in two tubes with a microfibre polshing cloth for about £10. I believe it's even certified by TUV which i think is a top german quality mark. Just rub the polish vigorously over the scratch and then use the finish to......well finish . Worked great when some scrote ran a key over my bootlid - highly recommended.
i take it you've tried T-cut, what about magic colour or T-cut colour fast
failing that you could always get a touch up stick depends on how many
scratches you have though if theres a lot then try colour fast that worked
for me
well t-cut is supposed to have very mild grinding properties
which are supposed to help reduce deep scratches and
completely remove light scratches, have heard that the
one called Mer is good but never tried it