Hi, Kando! No problem re the questions I'll try to deal with them in order! Quorn is readily available and actually, the fish is good if you go to local markets rather than the supermarkets (which are pretty poor by British standards). The Dutch don't eat big portions of meat so stuff such as roasts is out, although that won't apply in your case. There are several books which give translations for most foodstuffs -I'll dig one out later and give you the title, but my DH was given it by his company when he moved along with several other relocation/welcome to the Netherlands books.
My kids are now 9, 7 and 3 and we moved out her about 3 and a half years ago as Dh applied for (and got, obviously!) a job here. We put our kids into Dutch school for the 1st year - it was free, was just around the corner and we thought that as they had never been to a British school anyway, we might as well give it a go. The kids were fine and within about 5 months, were speaking Dutch quite well, esp dd who is good with languages. The reason we changed to international school was two-fold: firstly, ds1, then aged almost 7, couldn't read or write in English and was quite shy and lacking in confidence. The year group he was going into was where the schoolong gets a bit more serious and they learn to read and write but I knew that i wouldn't be able to help him as my Dutch is poor. I had the feeling he would always be 'behind' -not as good as the others in school as it wasn't his home language and not so good in English because he'd never learned it in school. I worried about how he would cope when we move again esp as this move would not be back to U.K.
The second reason for changing was more selfish: The Dutch school was in a little village where people had lived for years and their grandparents had grown up there. I had no one to go for a cup of tea with, was lonely and felt a real outsider and very conspicuous.
Now, our kids go to a school in Hilversum where we live which is international but is government funded so the fees are dramatically different to most international schools. We pay our own school fees and could not afford any other international option, but as it happens, this school is very good with an excellent approach to learning (very enquiry based with lots of questioning from the children, 'presentations' every few months of a chosen theme which fits in with the current learning topic. There are close links with a local Dutch school and my kids are very happy there.
I think if you are in an expat community such as Den Haag, you will find no problem in making friends, both for you and your children. Kids usually start playschool here at about 2 and a half and the fees are reasonable (my ds goes 3 mornings a week and it cost us Eu70 per month)
Must dash to walk the dog but any other questions, fire away and I'll check mumsnet later! xxx