Hi Ben, thanks very much for your help.
I am resigning because my working hours consistently exceed over 60 hours per week; my contract stipulates that I must work up to a maximum of 48 per week, and that if it becomes more than this, I have to raise it with my line manager for a solution. The response I received was "if you're not prepared to work as many hours as it takes, then I don't want you in my department, and you might as well leave". Aside from this, I am looking for a job with more money, and with less travel.
The agreement was signed as a separate document - it is a letter from the company to me outlining the terms, and my signature at the bottom is to indicate my agreement with the terms outlined.
Thanks for following up - no, I have not received your response. The last thing I received was:
"Thank you for your response. I will review the relevant information and will get back to you as soon as possible. Please do not respond to this message as it will just push your question to the back of the queue and you may experience unnecessary delays. Thank you"
If you could re-send it, I'd be grateful. Falling that, I could give you my personal e-mail address and you could send it there?