MM wrote:
I don't want to have to repaint an entire wall because of one or two
hairline cracks.

I believe I am right in saying that the Dulux paint matching service
only matches to the closest Dulux colour.

How hard is it to tint a colour to get an exact match? Or a match as
near as dammit so that only close inspection would reveal a
difference.

The colour is currently building industry standard magnolia, matt
emulsion.

MM

In my experience, you will spend a week trying to find an exact match, do
umpteen runs to the paint outlet, buy several different colours, and then
end up painting the full wall anyway, which is what I'd advise you to do
first, it can't take longer than a couple of hours and that includes
sheeting up and cleaning brushes etc.

And FWIW, there is no 'standard' magnolia paint, Dulux, Leyland, Crown,
Jhonstones and at least a hundred other paint manufacturers all make
magnolia, but there's not two the same.