DS is nearly 7 and no where near being able to tie laces or do buttons & zips, but is also tall and skinny so the easy on elastic trousers are either to short or don't stay up.
I found a solution! I ordered 20 of these off ebay for around £5, and put them on all his draw string joggers, and it works. I know it's not a life changing revelation, but it took me years to think of it, so thought someone might find it useful.
(In case the photo doesn't load, there spring toggles, like you get on bags)