Hello, Paul,
Marriage records for the date you want, 1786, are recorded in simple forms 3 to an A4 page so you can see they are not big. They contain little or no detail anout the couple being married, no parents or addresses They show as follows >>>
The couples names & whether they were OTP ( of this parish) or their home parish, the date & the name of the church, the name of the priest officiating, the signatures of the couple plus the signatures of the 2 witnesses.
The records for the church Spitalfields, Christchurch, Stepney are held on film at the
London Metrpolitan Archives
40, Northampton Road,
London
EC1R 0HB
Copies can be taken & if you are unable to visit yourself you can ask the Archives to do it for you & send it by post but there is a charge, I think it is now £8.
Hope this helps
Meliora