I am roughly the same as you, perhaps a bit further 'behind', to the extent I can afford/justify an airbrush (yet...)
I also have tried Halfords paints and found them very good in comparison.
My trouble is I painted a shell in Tamiya, and then just barely polished through to the primer... I daren't try 'repairing' any other paint in case it reacts. Unfortunately the model was built to replicate a friends car and intended as a gift.
