Get someone like Chips Away in or take it to a body shop. Nothing Halfords sell (or any other DIY kit) will do a proper job. You'll spend hours on it and it'll always look cr@p. Use the time to go earn the money to pay for the repair.
I have an 07 cmax and it seems to be a magnet fro shopping trolleys and stone chips. I used one of those halfords touch up kits but mine is metallic not so easy. If its a flat colour probably will be ok.
Didn't realise the car was relatively low in value. Just buy a scratch repair kit and do your best with it. Basically they usually have a coloured paste that you 'fill' the scratch with. make sure you let it harden for several days before polishing flat.