What the heck is wrong with my carrots?

What's orange and sounds like a parrot? A Carrot. That's still the funniest vegetable joke I know. Unless you know different. There's a comments box and everything. Come on 'ave a go if you think you're funny enough. Here's the thing. My sunny, sheltered, south facing plot has warm, rich, loamy, well drained soil. I live in the south east and we have no discernible rabbit problem. (foxes ate all the rabbits) For carrot growing you just add carrot seeds. That's it. I have everything that 90% of other plot holders across the country and the rest of the carrot eating world spend a lot of time trying to create. I can hear the other 90% of plot holder cursing me now. Oh you poor soul, with your rich loamy soil and sheltered south facing aspect. Talent is what you lack you oaf! The only way I know that my carrots are carrots is because I have litle white markers at the end of each row that says "Carrot". I put them there myself.

This year's crops of carrots have been worm infested and rotten. For every ten carrots I pick, six are inedible, two are under sized and only two are presentable. I'll be hoping for some proper frosts to kick the soil into shape and kill of some of the bugs that are doing all the damage. Clearly carrots are not fire and forget and I'll need to make more time for them next season.