We recently had our victorian house painted in F&B Cornforth White. We wanted a grey that wasn't too harsh as our house is also north-facing.
Going into the F&B shop helped a lot - they took us outside with a few of our favourite sample colours (the ones they have on wooden boards) to see what the colours looked like outdoors. Some had pinky undertones, some green, etc. We settled for Cornforth White and Ammonite, did two test patches, and decided on CW as Ammonite was too subtle. We paired it with a Railings door and think it looks great. It does have a creamy undertone, but we quite like the warmth it brings.
Our next door neighbours decided to paint their house shortly after we did ours, and they chose a darker grey (no idea what the colour is - you can just about see it in one of the photos), but to me it really looks harsh and a bit dull - not great on a miserable rainy day!
Your house is gorgeous and the features are lovely. I like how your neighbours have gone for a stand-out door colour - a nice nod to colourful Brighton.
(above: day time - cloudy day)
(above: morning)
(above: evening)
(above: left = ammonite, right = cornforth white)
(above: left = neighbours' darker grey, right = cornforth white)
Q