Smaller rescues are usually more flexible if ages of children are an issue.
Look at Black Retriever X Rescue (there's a website and FB group page). Obviously, mainly retrieves but they've also had cocker spaniels in the past so worth having a look. You could talk to them about what you want so they can contact you if appropriate.
Would you consider a slightly older dog? I fostered for Balkan Underdogs and one of the ladies involved has posted about a pure bred ESS - this is the text from her post (rather long!) and pictures:
ADOPTION APPEAL: Meet the gorgeous Pongo...................... Pongo is a pure breed English Springer Spaniel. He is 5 years of age. He is a champion dog in Serbia, and his owners want to give him up, purely because hes now past his peak for showing and will no longer win trophies in his own country. His owners are focused purely on show breed and not interested in this dog purely as a pet. Its a very very sad situation, but very very typical of the pure breed dogs in the balkans. Pongo was given up and is already safe in kennels in Hungary, and fully microchipped, vaccinated for travel and ready to be rehomed in the UK or Europe. Pongo is 5 years only. He has only just turned 5 years, so still young and plenty of wonderful life left in this gorgeous boy. He has been a spoiled pooch and needs to learn some owner discipline. He gets along really really great with all other dogs, no issues or problems, but, Im gonna be honest, he needs more training. Hes a bit clumsy on the lead, lazy................ used to being admired and shown and needs to learn to walk longer distances on lead, more than 500 yards. He works well for reward, but only reacts to training if rewarded. He thrives on love and affection and attention and is really really great with children and all other dogs, but he does like to chase the kitties. He isnt quick enough or smart enough to catch a kitty, but he does like to chase them if he sees them. He is very easily trainable through the reward system, but he does need some more training application having been a rather spoiled dog in his past. He as many trophies, and he also comes with a full pedigree too. He has won many awards for breed during his time in the balkans, but he has been given up as hes past peak. Very very sad I know, but this boy now just needs to be a loved pet, with a life of walkies and relaxation. Hes earned his retirement from showing. He just wants love and affection and somebody who can complete his training. Please contact me, Wendy Feather if you are interested in offering a foster or forever home to Pongo. He would give anything to live back in a home again with a family who want him for who he is and not for his pure breed status or how he looks. He just wants to be loved................... please share for Pongo and if you would like to adopt this gorgeous boy, please contact me for further info. Thank you. Please Share for Pongo.