You'll need benches surely? I suppose if you're intending to use it for crops only - then growing areas are important to you - but I have benches AND hanging shelves, and they're all full of seedling trays and pots of plants like fuchsias that can't go out yet.

Why not think through the use you're going to make of it, then decide.

I have concrete laid in the middle of mine so that it stores the heat from the sun so to keep plants warm at night & have one side to plant in the ground, the other side I have covered the soil with plastic and put pea shingle down in case I want to change things round & put in staging for my potted plants and seedlings and at the end shelving to use for what ever I want, Good Luck with yours and I should do what is best for you, "Happy Greenhouse Gardening" :o)

Thanks Spritzhenry & Ladyessex1!

I have full length staging down one side and shelving above - I intend to use the ghouse for toms, cucumber, peppers, chillies, etc. I only started growing last year, so I'm still a beginner, but I''ve opted for beds on both sides and along the back on the basis that I can always easily extend the paving area if I need to.

It sounds as if you've thought it through. Have fun with it! :-)