Looks like it hasnt gone through the primer though which is good news, you could spend a day with a halfords touch up set as one option (probs cheapest) but results are dependant on a lot of things and the cold weather isnt gonna help, or they sell Farecla G3 Scratch remover paste (currently with free applicator in some stores) which I've used in past and its way better than T-cut (guess where I work lol), or, You got any decent body repair centres near you?
Scumbags, no other words for them you might be lucky and be able to polish out some of the marks with a rotary polisher?
Best bet would be to take it to a couple of bodyshops and get their advice and/or quotes!
I'd say polishing is the only 'DIY' option (and only really of you have access to a polisher - might be worth a stab by hand). If it needs paint then I'd say it's a bodyshop job as the scratch is so long. Touch up kits are ok for stone chips but not much more.