Camellia (not C. reticulata) you need inter nodal or leaf bud cuttings, taken in summer, or hardwood cuttings in autumn. C. reticulata you can layer. Ilex (holly), cuttings with a heel in early autumn. Google the names of different types of cutting for instructions...

with holly you need to wait until the new leaves have stopped expanding before taking shoot cuttings about 3-4 inches long. Remove bottom leaves and insert into sandy compost in a pot. Keep humid and also, bottom heat is useful. They take quite a while to root so be patient and don't pot up til you can tip them out and see new roots. Pot them up into 3inch pots and keep them in a cold frame or greenhouse for their first winter, as even though the full grown plant is hardy, the rooted cuttings are prone to die if not protected.
With Camellia, they seem to root best from vigorous new wood, so, unless you have some strongly growing new shoots it may be best to to prune a branch or two in order to stimulate some nice new shoots. Then take shoot tip cuttings in early summer about 4inches long, remove bottom leaves and trim to just below a leaf node. Insert into sandy, ericaceous compost and use bottom heat (window sill heated propagator etc). Then wait etc, as for holly.

My sincere thanks Bamboo & Volunteer for your guidance; I'll give both a try!
Rozz.