[Casey76]

I've done a bit of weed clearing, and it's possible I might have enough space to plant my brassicas actually in the ground  rather than keep them in containers.

However the area is bordered by two hedges, and it is quite shaded for 50% of the day.

I will be trimming the hedge back as much as possible (if it ever stops raining!) (beech one side and yew/conifer on the perpedicular) but as it is my boundry, and i prefer a little privacy from the road, it will remain 6ft high and still shade that area of the veggie plot.

[tosca100]

My little plot has limited direct sun and most things grow well there, given the right weather. My brassicas go in late, when and where there is space, but rarely get any sun in the winter as it has six foot borders all around. Give it a go, it's got to be better for them than pots.

[Kleftiwallah]

The brassicas will have plenty of shade when the pan lid goes on! 

Yes,  I think they will be O.K. with a bit of shade.   Cheers,    Tony.

[devonbarmygardener]

My plot neighbours helpfully chose the most inappropriate spot for their greenhouse - right next to my plot so that corner is now shaded for the latter half of the day

The cabbages I planted in that corner this year are actually doing really well. The shade might even be keeping some of the flutterbys away.
Now that would be ideal!

So yes. I would say brassicas can tolerate some shade.
Try it. If they don't work thentry something else there next year.