It's v tricky to do state schools from overseas. You can't apply until you get back, so you will have missed opportunity to apply for your DS going into Y7 in Sept 19. (You would need to apply in Y6). In a similar situation to you, we went for independents as it was more certain.
To research independents, best resource we found was Good Schools Guide, at least as a starting point. Subscribe online and you can search potential options.
Like you, we could live anywhere, so had quite a large search area for schools. We started by finding secondary school and then picked a prep/primary for our other child close to that and found a house close to that.
In your situation, think you have a few options -
- a prep for Y7 and Y8 for DS1 (probably taking Common Entrance) and then move to secondary in Y9. (However, FYI, in this case, you'd have to check process for entry in Y9 , as for most/many of these schools they will be doing the pretest in next few months, getting their conditional place in Y6.) You may find they offer you another route as you are overseas.
- Go straight for independent secondary with an entry in Y7.
- Straight through school with prep and secondary.
Knowing what i know now, if the school you choose has Y7, I would go for that option over going for a prep followed by Common Entrance and joining in Y9. And then prep for your younger child. (My reason being that given the application process for Y9 secondary you would basically need to pick and apply for a prep and a secondary now in any case for your elder DC! And also, Common Entrance year (Y8) is not particularly interesting - loads of exam practice and fair amount of pressure. Fine if you have been leading up to it all through prep, but don't think there is any great advantage if you have only been in prep a short time.)
A few options to look at around Surrey. Downsend (now going to 16) has already been mentioned above. Other prep schools in area - Danes Hill, Kingswood House (also now goes to 16, boys only), Aberdour, Feltonfleet.
Secondary schools you could look at - St Johns, Epsom College, City of London Freemans, Reeds (boys only), Reigate Grammar, Box Hill, Ewell Castle, Cranleigh, Royal Grammar School, Hampton, Reigate Grammar. If you wanted to live closer to London, you could look at JAGS, Allyns, Tiffin, Dulwich etc, Kingston Grammar (also a whole host of other grammars Sutton, Nonsuch, Surbiton,) Most of these (possibly all) go from Y7, some from earlier. Some more academically selective than others. There are lots of others - choosing a rough area and doing a search on GSG will give you a good list. (List above mostly co-ed/boys ... if looking for girls there are other options too.)
Then ring round admissions to get a better view of application process. You can even ask secondary schools which prep schools send kids to give you a good list for your younger DC.
We visited a range of abilities and areas to get a feel for the schools and then were able to narrow down to short list for application. Didn't know the academic level of our DC so did apply for a few.