I agree that it is badly curdled. Custard per se is finicky about curdling, it has an about 10 degrees celsius "right" window - if it doesn't reach that temp, it doesn't set, if it overshoots it, it curdles. Lemon custard is much worse, because the acid curdles proteins even without high temp.
The tricks you can use: 1) warm everything really slow. It is a little-known fact that the speed with which eggs are heated determines the temperature at which they will curdle (source for this counterintuitive statement: Cookwise, a book by the food scientist Corriher).
So, leave your eggs out overnight before starting, so you will be sure that they are room temperature and not fridge temperature. Then set the oven very low. It could be that an experienced cook can get away with 350 as in the recipe, as they may be able to pull it out quickly. You will be on the secure side if you set it to maybe 230 and then bake by internal temperature, as Saj suggested.
Also, if you still experience trouble, you could increase the amount of sugar in the recipe. This will reduce the chance of curdling too.