Wow, that would be a good evidence of sole custody, and make sure when you make cover letter, put all your reasoning, declaring them in your first application was really good, dont worry much, just show to the ECO that you can support 4 kids, hmmm by this stage having ILR you can able to get some publc funds now, you can start preparing now and dont hesitate to ask here in the forum all your querry,

Joe(moderator) will be happy to support you (joke) where is Joe now