I gather that Polecatsteve might be looking for something really simple.
Take one of the branches, easiest with one growing low down, and bend it down until it touches the earth (scrape a wee bit clear if necessary or partially lift a turfy bit and put the branch under it and peg it back down with a wee bit of stick shoved through the turf) and pin it down someway or other. A bit of willow folded over like a wooden clothespeg, (or a bit of fence wire, or an old tent peg) shove both ends into the ground one either side of the branch you're pinning down, works too.
Leave it alone and by Autumn it'll have grown roots underneath the bit that's touching the earth. Cut it free from the main plant and lift out your rooted cutting. Keep it moist (not hard here
) and plant it somewhere else.
Result = new plant without killing or uprooting or splitting rootball of the original
M