Right now is the BEST time to separate them! Fill the pot with the medium you're using. With a pencil, make a hole in the medium. Using your fingers only on the leaves (not the stem or roots) use a small spoon to carefully dig up a clump and separate the roots by gently vibrating them. Using the pencil, guide the root into the hole. Gently press the medium against the root and stem. Bottom water in a tray and empty the extra water. Plants do much better the earlier you separate them.

I use Pro-Mix for all seedlings but you may want to read what others recommend for potting on bigger plants.

@Susanzone5, Thank you for your advice. Snagged a quick photo - not the greatest - and hopefully all goes well from this point onwards. :)