spuds gone wrong?

am begining to think my spuds have gone wrong
planted them middle of april.
1st earlies are rather random ie plant then space then plant its as if every other seed spud has failed to develop.
2nd earlies are slightly better
main crop have all shown

1st and 2nds no flowers
main have flowers

cannot at this moment recall their names but were all maris something.

anyway am a novice at this so i am still learning, i get quite frustrated when i see everyone elses thick and bushy plants.

as a consolation my cabbage and caulis are thriving

All the Maris potatoes flower, according to The British Potato Variety Database.
I think it's just too soon for the earlies, they usually take 12 weeks as andy said, but mine took 14 weeks this year because of the cool weather 

But can't think why you have a few gaps...some seed may have just rotted in the ground

Both sets of taters are flowering now, one lot are pink fir, which I thought would flower later, the other lot are earlies....but the pup ate the label so don't remember what they are.

It's a late year due to the frosts well into May plus it's been much drier than normal.
I've started watering my earlies which is the first time i've ever watered potatoes.