Drill a few vertical holes in the stumps and very carefully
pour in some Roundup. One application should be enough.

Do not spray the stump.

Roundup is a systemic herbicide which is normally absorbed
through living green matter. Your stumps have no green
matter left, so you need to get a fair amount into the core
of the remainder of the tree. Spraying the stump is basically
a waste of Roundup.

=============

Anthony wrote

Hi there,

I have recently removed two trees from my garden as they were becoming
too big and were blocking out too much sunlight in certain parts of the
garden. They are c8 inches in diameter and i have managed to chainsaw
my way through the stup so that only 4inches remains on the one and
about 10 inches on the other [due to its location it was difficult to
get any lower].

Is there anything i can do to stop them re-growing/spruting or is that
it?

I hope someone can advise.

Regards,
Anthony