If you have loads of time then try a climbing hydrangea. Takes a couple of years to get going but then grows at a 'normal' rate. There are clematis that don't mind the shade but if you want perfumed you could be out of luck. How 'shady' is it? If it gets a few hours of sun a day then a lonicera (honeysuckle) would certainly fit the bill. Maybe the roof would cut light down too much though but one of mine does great in 90% shade.

Star Jasmine (Trachelospermum jasminoides) does fine in the shade, here, though that might be a little too much perfume indoors! Pinwheel Jasmine (Jasminum nitidum) might be even better: it has a longer bloom season, and the perfume isn't as rank. Arabian Jasmine (Jasminum sambac) could work too, but it will suffer more in the winter.

What is the coldest temperature that you could expect to get Bertie? If it doesn't get less than 8-10 degrees, one of the best would be Hoya carnosa.

Some members of Passiflora might be an option too though I find their growth a little untidy.

Thanks for all the ideas so far. Temperatures near the door where I'd put it get close to freezing, probably about 2 or 3C, while at the back it stays warmer but is darker. Part of the problem is I've already got passiflora edulis everywhere which is great for the fruit but not for scent and appearance. Star Jasmine or one of the other jasmines sound a good idea, and I'll have a look at one of those.
Going to the first plant sale of the year at the Chateau of Bourdaisiere tomorrow so will have a look at what they've got there.

Have you thought of trachelospermum jasminoides? - And one has to be very careful because 'asiaticum', which has a faintly cream centre instead of being pure pure white, is often sold as trach. jas. I first saw it growing like a weed on the north side of walls in the Pope's garden at the Vatican. I have grown it outside and had it flower well for years in 14" pots shaded by the angle of SE facing house wall and a NE facing one, and fill the air with its scent of vanilla and cinnamon. I am now trying it on a SW wall facing straight down the Bristol Channel to America and it is not happy, I am almost sure because it is being baked!

T. asiaticum is also lovely though:-) Don't knock it for the creamy touch to its flowers ;-)