Thank you for the warning. I had planned a Wickes kitchen with 1000mm wall units and I have larger than average loads of tins and plates.

Ironically the 1000 units are fine because they have a central pillar to support the shelf, the 800 units don't hence the problem.

Thanks Moron Watch, will probably try the divider suggestion next, do you mean wall plugs when you mention 'plastic plugs'? I was wondering about drilling a longish 3mm hole then whacking in some 5 or 6 mm self tappers. Would plastic plugs be stronger?