Really sorry to hear that, it's no joke when all your hard work is destroyed by pests (where we used to be it was pigeons and deer, not been here long enough to know our main enemies yet).
The sweetcorn is unlikely to regenerate, though a few might (ours got eaten by mice - not happy!). Give the pak choi and purple sprouting a chance, it depends how badly they were damaged, but hedge your bets by buying in a few young plants if you can (seeds would take too long to establish at this stage).
We used to net absolutely everything and are doing the same here, just in case. Keep going, it will be so rewarding when despite the set backs you are harvesting your own fresh produce. The sun is shining here so I'm sending you an optimistic
and
that the plants flourish.