Thanks. I didn't know if I had that option. I will do the letter and I think I have to let it go.
Office of Fair Trading said I had a very good case of defective goods (that sounds so harsh.....) but if I take it to a tribunal there is a chance that I could get ordered to return the goods for the refund and repairs. A chance I am not willing to take. As much as the money would help so much my boy is far more important.
Thanks everyone for your input and advice.