Swede tops gone mad

I had some swede plants left after putting the rest in my outside bed, so I bunged them in my polytunnel border. Now after 2 weeks the top leaves are like dinner plates. Would too much top growth stop the swede from bulbing up and if so, would removing some leaves like you do for celeriac be beneficial?

Yes, I experimented with swedes in my tunnel last year and regretted it. Clearly they liked it in there but the top growth was so lush they just about took over the entire bed.

My swedes have gone a little mad too, and I've never grown them, so dont know what to expect....

They are under debris netting, and the soil, is sandy and not very rich, so I dont know why mine have gone mad like this?