I've got a 3 year old joining me so their 2 year check was done at another setting. Do I need to request a copy of this at all or is it not relevant now child is older?

You could ask the other setting or parent for a copy but whether they give you a copy is another matter. Just do your own starting points and ask the parents to complete an "All about me" form so you know what the child is interested in and can already do.