This is an interesting comment. I was considering hiring a space for a week or so to build as much as possible off site to minimise disruption. Then bring it in and screw together.
Your ideas tie in pretty well with that. I think I need to familiarise myself with sketch up and come up with some ideas.
Thanks.
Work out the footprint you've got to work with and draw it up to scale on graph paper. Then work out what you need to fit inside and how you want to use the space so you know where doors and window need to be, which way the roof needs to slope etc. If you've got units, desks, benches etc of a known size that you need to accommodate, you can make scaled cut-outs of those from card or paper and move them round the plan so you can see how they'll work in the space. If your 10x8 footprint is just an average size and doesn't need to be stuck to rigidly, playing with these scale cut-outs on your drawing will tell you if you need to tweak the dimensions or the shape.
If you're an IT clever clogs you can maybe do this on a computer, but I'm not so for me it's old school on paper, but as long as it's to scale that approach works extremely well.
Go with 450 mm spaces (not centres) between the studding for the walls and then 450 mm insulation bats will fit in snug.
Floor wants to be 6X2 joists covered with 18 mm structural ply. I wouldn't be tempted to use sterling board as it's rubbish, or chipboard flooring as it's expensive, easily damaged and needs covering. Use treated timber for the frame but I'd use natural wood treated with preservative for the cladding. I'd treat the ply on the floor as well. You could even build galvanised steel feet into the corners of the floor so you can set it on the pads and bolt it down from the outside.
You basically build the floor section first, then the walls and offer them up dry at the construction site before final assembly.
The roof needs to overhang the eaves on you gutter side (allowing for the thickness of the cladding) by 2.5", then the roof will drip into the centre of 4" guttering.
Given the modest size, it should be light enough to enable you to fit the roof covering - if it's something light like Cladco - at the dry build stage so the whole thing can be assembled fully finished and dismantled the same without any deconstruction. The roof can be secured to the walls with galvanised wall-plate straps accessed through removable panels in the inner ply. I'd probably insulate with PIR between the rafters and floor joists as well. The finished panels will be fairly heavy but two or three of you should be able to assemble and dismantle easily enough.
Electrical wiring can be surface mounted inside in trunking with junction boxes where the panels join so it can be easily disconnected if you want to dismantle the building and move it without disturbing the final-fix electrics inside.
The detail of how to weather-proof the corners where the cladding meets is straightforward but not easy to explain in writing. Feel free to PM me if you want any help.
Do source and cost all your timber carefully though before you dive in because it's heinously expensive at the moment