Jollop, sprays, touch up's...they do only one thing; and that is to mask the scratch. They only 'nourish' the plastic at a surface level and are temporary shine agents.
For a repair - First if all you need to match the surfaces again using something like a super fine 3M softpad. Not the old scratchy green pads (Scotchbrite).
Try this on an inconspicuous area first.
Once the scratch is at a similar level to the surrounding material, the trick is to heat up the plastic to release the oils that are held within it. They will come to the surface and give the same appearance as the rest of the item.
I could do this in around 30 minutes with a heat gun. It takes patience and a gently, gently approach.