First earlies (Latona) with pictures

Hi, We had our first picking yesterday, yields down by half re last year, been in for 12 weeks and look as if they need a further 2 weeks!! The potatoes had splits presumably due to the weather of late which caused the 'black ' areas' - any comments please.  When boiled they proved to be very tasty, slightly sweet.

Could be black leg if the stems had keeled over.

Could be early blight if you had that on the leaves.

Thanks, Don't think its black leg or blight as the helms were OK  Do you think the crop is fully developed?  Should I wait 2-3 weeks or so before I harvest more.