Hugs hun, sorry you've had such a bad experience. just to address your questions as best I can
I just read about deregistering, so I will do that. I have to write to both the headteacher and the LEA here (gained advice from the LEA this morning). The LEA said they will just do occassional inspections to see we are educating them properly, is this the norm? They like to claim that it's normal to get inspections but it's a load of crap. They have NO right to come and inspect you. Tbh I would never let the LEA come and 'inspect' us as I feel I would just be opening myself up for their interference. It's also important that you know that you do not (if you are in England) need permission to home educate or deregister your kids. Please take a look at the Education Otherwise website so you know exactly where you stand legally.
And will they let me know when they are coming, I mean what if we are out, will that be held against us? As I said, they have no right to inspect you. They may ask if they can meet you and discuss your provision and tbh that is totally up to you. If you say yes it should be by appointment and in the location of your choosing. If someone just turns up at your door to 'inspect' or even discuss your home edding, DO NOT let them in. Ask them to request a meeting with you in writing and then get advice from other home educators of the best way to handle things.
I have to admit, the idea of them taking my children away from me for home-schooling terrifies me. Is it a common thing? No it's not common. Where it has happened it's usually been as a result of the parents not having a proper knowledge of the legal procedures for deregistering their kids, or because they've been too accommodating with the LEA.
Would you say that at first workbooks are a good idea? I think given the way we are leaving the school, that I need to 'prove' to the LEA that we are educating them properly, and workbooks/print outs. folders or work etc seems to be the only way I can be sure that they can SEE we are. Does that make sense? Personally (taking into account all that I've said above) I would avoid workbooks for the time being and just let your children have the time to 'de-school' and relax again and rediscover their love of learning. If you're worried about evidence for the LEA (though you really shouldn't be) keep a journal about all that you do and take photos of the places that you go. Remember that every time your child helps you cook, reads a book with you, helps you with DIY, helps in the garden etc they are learning.
Hope this helps