It sounds like whatever you do possibly achieve in this porch wont give the right results and the missus will make you move them anyway.
Im quite lucky – we live in a very small house but there is a walk in cupboard upstairs where I store all the bikes and gear. The other half wants them in the shed, I completly refuse this idea.
Anyway, I suggest the loft. Get some boards (B&Q do them cheap) board it out, or even just half of it, get a loft ladder and job done. Everyone is happy then. Bikes are safe and not in everyones way downstairs. Wheels off, carry them up.
Yes it’ll be a bit of a faff dragging them in and out when you want them, but its that or move house 🙂 Or the shed where at some point they will be stolen. If we didnt have our cupboard, I’d be using the loft.