South West UK
edited July 2021
I think "Love and wishes" can be a bit temperamental, l have lost mine over Winter in the past, and l'm a lot further South than you. Taking cuttings is a good insurance.
I usually do mine around mid to late August. You can keep them in a pot overwinter, if you don't have a coldframe and some fleece, a bright windowsill or a porch that stays above freezing should be fine.
Well-rooted young plants from cuttings will take a bit of cold, the same as the parent, but what all of them need is for the rootball not to be wet and then frozen hard. They don't need artificial heat but an unheated porch or conservatory would be fine, or a windowsill in a cool room. Alternatively you could keep them outside (sheltered so they don't get soggy roots) and move into a shed or similar if it gets really cold. The top growth is supposed to die back so they will take a few days in the dark in the depths of winter while they're dormant, if that's your only option.