Hi, I'm new here, this is my first post :) Sorry it's so long, but wanted to expain properly.
To start at the beginning, DD2 has just started year 1 at the same school she was at for reception. DD2 has a fairly uncommon but not unheard of name, and although it is not spelled the 'usual way', it is still a perfectly legitimate spelling. We went for the less usual spelling partly because DH and I felt there was room for teasing with the usual spelling, and partly because my mum is from Honduras and the less usual spelling is Spanish. Last year in reception we had no problems at all, her name was always spelled correctly, etc.
This year, DD2 came home from first day of reception very upset and told me that her new teacher could not spell her name. I told DD2 not to be silly, was probably just a handwriting thing. But sure enough, when I took DD2's reading diary out of her bag, the teacher has written her name on the front with the wrong spelling. Apparently it was the same story with her peg, tray, etc. But last year DD2's name was always spelled correctly, and the data collection form we had sent home at the end of reception definitely had the correct spelling of her name (DH and I have dug out the photocopy we have at home to check, definitely the correct spelling). So we figured it must be the teacher spelling her name wrong.
So the next day I had a word with DD2's teacher, explained calmly that DD2's name is spelled X way not Y way. Teacher gave me a funny look, so I explained that DD2's name is a perfectly legitimate spelling, just less common. Teacher was very apologetic and changed name tags etc in the classroom so DD2's name was spelled correctly. Problem solved.
Expect that in DD2's reading/homework diary, teacher continued spelling DD2's name wrong, the same way as before
. And according to DD2, when she marked her work she still spelled her name wrong, eg, well done 'wrong spelling'. I didn't want to get off to a bad start with the teacher so early on in the year so told DD2 (who is normally really rubbish about speaking up) to put up her hand and tell the teacher gently that she is still spelling her name wrong when she gets her book back and notices this, and if by the end of the second week this mistake was still happening then DH and I would go in to speak to the teacher.
Well, halfway through the second week the teacher went off on sick leave (personal reasons) and still wasn't back by half term. So DD2 has had a supply teacher, who has had no trouble at all spelling her name correctly, therefore there was no issue.
This week, teacher was back, and like before, is STILL spelling DD2's name wrong despite it now being spelled correctly on the front of all her books (DD2 has verified this and is usually very reliable, so am inclined to believe her). Now we don't know exactly why the teacher has been off although there is rumour about the playground that she had a miscarriage, in which case my heart goes out to her and I accept that allowances may have to be made for her for a little while. But surely it's not too much to expect her to spell DD2's name correctly? 
DD2 was very upset about this again during the week and quite frankly I don't blame her, so I promised her I would go and speak to the teacher again today after school if we didn't have her name written correctly in her reading diary by then. Well, the TA who wrote a comment about something unconnected this week seems to have managed the right spelling, but when the teacher listened to her read yesterday and wrote in her diary once again she spelled DD2's name wrong. So as promised, when I collected DD2 today I went in for a chat, explained once again (perfectly polite and calm!) that she was spelling DD2's name wrong. At which the teacher promptly burst into tears, said she is fed up of parents like me hassling her over such petty things, particularly when she is having such a difficult time at the moment and that I don't understand how hard her job is, before running from the classroom and leaving a baffled TA to escort DD2 and I out. No, really 
So what on earth do I do now?