Potato Foliage Died Off

I went for a weeks holiday last week and when I came back all the foliage on my spuds has yellowed and died off.

I have a row of Wilja and a row of Kestrel, but as I didn't get them in until the middle of May I wasn't expecting them to be ready until the middle of September.  I know bot varieties are classed as 2nd earlies but I read both could be treated as a maincrop variety.

Am I OK to leave them in the ground until I need them or should I get them up ASAP?  It nearly killed me getting the ground ready for them, I'd be gutted to lose them now.