What is your budget, and how many beds do you need? As you have a toddler, probably the first question is, do you have a preference for a particular type of primary school? If you look at the Greenwich interactive offers map for primary schools and see where you need to live for each school. There will be areas / streets where you are not close enough to any of the closest schools to get a place, so you need to be very careful, as your dc could end up at an undersubscribed primary a bus journey (or two) away. Applying for primary school comes round much more quickly than you think it will!
In terms of Eltham Park - Unless you are going private, or are a long-standing practising catholic / Cof E attendee (who can meet all the reqts for application), it is probably best to look in the few streets immediately around either Gordon or Deansfield, but make sure any property is well within recent years’ offer areas. The offer areas are quite small.
So look and see what some of the housing options are in your budget, and are also comfortably within the historical offer areas for the local primary schools, then overlay on that the offer areas for secondary schools (as unless you will be upsizing in 5 years, it is best not to have to move again for secondary schools! Also bear in mind the entry requirements for the Voluntary Aided Schools.
Also, the grammar school offer areas have been steadily shrinking year on year. Chis and Sid / Beth’s / Townley still offer to a large chunk of Eltham (check historic distances though), but Bexley Grammar offer area has shrunk to reach only the edge of Eltham. Eltham Hill (girls, non selective) is fantastic. And there are other good secondary schools.
It is a fantastic place to live - lots to do, but still very leafy and calm. When we moved here our house and car insurance went down significantly (it seems to be a low-crime part of the borough). Great schools, at both primary and secondary, and access to schools in neighbouring borough. There have been quite a few families move across the borough from Greenwich to Eltham, as you get much more for your money, close to good facilities, and there are so many more schools nearby (especially at secondary) compared to Greenwich.