What parental leave in 2 blocks means?

Hey,

I wonder when I take 6 weeks of parents leave for summer holiday for my kiddo 2 years in a row, does it mean I can't use my leave anymore?

I'd only used up 12 weeks of 26, but as I understand I'd be locked out of using the rest as you can take it in only 2 blocks.

Is 2 blocks for a year or per child or employer? Would be done only at employer discretion or is completely banned?

Would be handy if you can take it more times as all young summers would be sorted for childcare and it would alleviate some stress.