Our Pentland Javelin went in - at home - on 25th March, and were possibly too close together, but we just said 'S** it' and they started to get dug out 12th June, so you're not far behind!
Have to admit they're the best crop we've ever had, and when the halms dry off, as they're doing now, I'll have some space for a late sowing of summat - not sure what yet, but we'll think of something!
We're lucky, as we have the garden hose to keep them going, whereas when we had 'The Patch' down the road, it was a nightmare, especially as the frost kept appearing when we didn't want it to...