I`m assuming you bought your car in Scotland ? Scots law governs the sale, not English law. You need to make sure you have copies of the seller`s adverts ( for the car and the separate parts), and make sure you have copies of any emials or the like.Finally you should write down, with dates, what the seller said to you or your dad about the condition of the car - everything, it all goes to build a picture.
At the same time as going to see a garage to get an estimate of costs to fix you might want to think about some Scots legal advice, you could start with a CAB but if I were you I`d look for a litigation firm,ideally on a recommendation from someone else, some will do a free initial consultation. You need to make sure legal costs don`t run away with you so all you are after to start with is a quote for a realistic opinion on your legal position - fix a budget for that opinion and don`t exceed it. Next step would be a letter before action, again fix a budget (but for an £1100 car bear in mind that you can easily run up more in costs than you could recover in damages even if successful in Court so fix a sensible initial budget and make sure you can afford to lose it, and don`t get carried away in the process).
Do you have legal expenses cover as part of your motor insurance, will that respond ? Are you in a motoring organisation with access to legal advice, can they help ?
My gut feel is this would not be an "easy" legal case from what you have posted so far, its not obviously legally complex but it is likely to be evidentially more complicated than it looks, for either breach of contract or misrepresentation, but to be more certain you really need an informed opinion from someone who owes you a duty of care for the advice they give