This is the link to the LMA's research service
http://www.cityoflondon.gov.uk/Corpo...ch+Service.htm
It looks quite expensive though! You could email them with the information and ask for a quote perhaps. Or if you post a plea for help on here someone may be able to go and look for you. Ancestry are putting a lot of LMA records online but whether Abraham's will ever be one of them is debatable!