Bebespain - I have a little girl who is 3 in November. At the moment she goes to a small guardaria for 5 hours a day. She seems to enjoy it. We decided that she would go so that she could pick up the spanish language - which she has amazingly. And so that I could have time for me to learn the language too (and clean, iron and cook).
She is able to start at the proper school in September (3anos) which I too am reluctant to do. They do look ever so small but I think that it is quite fun for them. Again it will be 5hrs a day.
I do know of many moms whose children go very early for breakfast and stay for lunch so it's a very long day compared to my kids.
I am sure your little boy is having a fun time. Usually the classes are really small compared to the UK anyway. My son was in 5anos last year and there was only 12 in his class. They do alot of fun stuff and lots of playtime.
I think my son when he went from 5anos in Infants to Year 1 in Primary was a bit of a shock for him. He complains now that he only gets one playtime. But it is a good stepping stone for them to get used to the school system and play with other children.
The UK does have more on offer for toddlers and preschoolers. From what I remember the UK provides a nursery place for 4 year old which is usually 3 hours per day. Not entirely sure but soon I suppose I will have to research. Because yes, we will be moving back permanently. We want to get the eldest into secondary education as she is nearly 12 so it's getting quite crucial for her.
It's a shame that we have to move back as there are so many lovely things about living here, especially the weather. Although we are in the cooler north, it is still better than the UK.
As for your situation - what are the school hours? Mine start at 9.30 till 2.30 and have lunch with me at home. I think it flies by.