A wisteria question!

[OuiOuiMonAmi]

OK, so I reeeeeeeally want a wisteria. I've got a warm, sunny wall and have taken up a paving stone so that I can plant one. But now I've realised that I don't think my wall is big enough! The wisteria would run over a patio door and the brick above the door is only about 1 foot deep - so the flowers would hang down and be damaged if we open the door! Above the brick is a plastic fascia board - I don't suppose that would be strong enough to hold a wisteria, would it? Also, we're a one-storey house... I know wisteria can grow hugely tall, but, if I find a way around the patio door problem, could I train it horizontally at a height of about 3m?

You can grow wisteria as standards in pots, so I don't think size would be a problem. You need to think about how you would support it above the patio door if you can't put anything in the plastic. Could you build some sort of arch or pergola?

yes you can train it and keep it to the size you want but from your description I cant visualise where it would go

You can keep wisteria any size you wish. You just need to prune it. And yes it should be enough to hold it, but I am also finding it hard to visualise

So we knocked some nails in, then strung some metal wire between them, there’s about ten foot between the nails. The wire holds it just fine. Mines starting to flower now.

That's great, thank you all!

Despite what some people say they don't do well in pots.
Consider one line of wire above the door (you can get varieties like domino which have short flowers) and building a pergola for the rest.