After more research than I care to remember we went for Ikea Bror shelving. It's made of a thicker gauge of metal than the other stuff I've seen, and it's all galvanised steel - no chipboard shelves to eventually go mouldy etc. Will get a third one eventually.
Recommendations on garage shelving?
Looking for 900x1800x45 and 1200x1800x45 or similar.
Not so keen on the bright orange and blue shelves, prefer the silver/grey/black finishes.