Sorry if this is getting dull, but I just found out about Haringey's Interactive UDP Map which shows all conservation areas, historic sites and other areas in the borough categorised according to their handling in the unitary development plan.
None of Harringay is a conservation area. The Ladder section is a restricted conversion area. The meaning of this is covered in the Haringey UDP chapter on housing. Conservation areas are also listed in the Haringey UDP Schedules at schedule 12. (The whole UDP can be accessed at Haringey UDP