I notice that you are located in Pinner, Middlesex. Google tells me that this is part of greater London. So, as an alternative you could go to the Chilean embassy [or call them] to find out if it is possible for a foreigner to get access to the Records held by the Regístro Civil and, if so, how to go about it.
Embassy of Chile, London
Address: 37-41 Old Queen St, Westminster, London SW1H 9JA, UK
Hours: 9AM–5:30PM