Devon Pinks

Hello - I have some successful Devon Pinks in my little borders which have turned into lovely plants, I know how to take cuttings,  but have an unheated greenhouse, and the limited window space in the house for cuttings is running out !  Live in N. Yorks

So just wondered if it is all all possible to divide/split and how to do ?  With any aftercare help

Any advice much appreciated - Louise