I just rang them up and asked for a form but I'm pretty sure you can apply on line. Your claim starts from the day you request the form and if awarded it that's the date you get paid from. You are given a set time to fill in in, can't remember exactly how long but I think it's a good few weeks. I would take the form with you to CAB but I suppose you can do it either way and they'll help. If it were me I'd do this asap and speak to the gp as soon as you can to give him/her time to compile the letter. The more supporting evidence you have the better your chances. Feel free to pm me if I can help at all. LOL I'm no expert but have gone through the process quite a few times. Please don't be put off by the form when you get it 'cos it's a b*gger of a thing to fill in.