Brassica cross-pollination

[wandoqebu]

I have a bed of different brassicas [at the time I thought 'keep them all together for easier pest control'] which overwintered - kale, sprouts, broccoli and cauliflower - and since they are all Brassica oleracea they would have likely cross-pollinated (idk if they flowered at the same time tho). Is it worth saving the seeds that are now forming to plant next year? I find brassicas tricky at the best of times, so am wondering if it's best to just start fresh with true variety seeds... what would you do?