You should really prune it after flowering in May/June if you just want to tidy it up, but can also prune it about January. This is usually done for renewal, as they do tend to get a bit leggy after a while. Mine are about 8 years old and about 2 metres tall. If you do it in January, cut about a quarter to a third of the stems back to about 12" from the ground which encourages new shoots (it's a bit like a blackcurrant in that respect).
But if you are going to move it (I've never done this), just in case, I'd take some cuttings first. They do root easily in a 50:50 sharp grit and compost mix. Note: I believe that you can't sell cuttings this one as I think it is still protected under Plant Breeders Rights.
