Indoor/outdoor? Lad I know has a body shop in Wigan with a big yard to the rear where a few local traders store their spare cars/px's etc. It's not a fancy heated barn if that is what you're looking for!
I stored a couple of mine in South Warrington (Appleton Thorn) - They were in brand new shipping containers, well ventilated etc - £25 per week if I remember. Secure yard with your own remote control to access the gated yard. They were called Roy Trevor if you fancy trying them