Hi well if you google Essex Records Chelmsford their web site explains things,but the cost is £10 for 24 hrs and £20 for 7 days, the web site is SEAX,i thought you might be some distance away,as I say before it was possible to access the parish records on line I used to do look ups at the record office,now well people like yourself can look the records up,you can download the images,it is best if you know where you want to look for records,get a map of Essex so if you look at a parish and find nothing then you will know the nearest other parishes to look up,it will not take you long to work out that some of the parish records have deaths,bap,and marriages in so there might be 120 images but by looking at whats in the records you know that you need to go to at least the 70th image before you get to marriages,I am sure you will work it out.