Briar scratches

if only surface marks then a polish with autoglym would probably remove/disguise them

Try silky.
It is a cutting paste for caravan and Motorhome panels. If you do use it apply with a soft damp cloth in small areas (about 2' x 2') removing it with a different cloth and polishing with a polish before going on to the next area.

Silky is slightly abrasive and must be applied with a lot of pressure (elbow grease) otherwise it will make very little difference.

Good show.

I bought it in halfords there own brand in a yellow tube

jeez it's want to be either very badly anodised , or mentally coarse compound . But anyways , the alu panels on the outside of a MH are pianted usually.