A bit of a "piece of string" question

Depends what you want, evergreen,? Flowers? Live near Leith, London or Lostwithiel?

Have a browse here to narrow down your choices

https://www.rhs.org.uk/plants/search-form

Sarcoccoca is a good one as it is evergreen, flowers with strong scent in the depths of winter and depending on which one you get either black or red berries. enjoys shaded position too.

SBG's selection would be one of the best, especially as you will be passing it when you go in and out in the winter.

I have Sarcococca in a tub beside my north facing front door. It smells wonderful when in flower and is doing very well. It does produce suckers though after a year or two so you need to pull them off. I love this and am so glad I've got it.