You asked a legal question and I gave you a legal answer. The correct legal answer, to the best of my knowledge. I appreciate you don't like it.
Corby went one step further to explain the right of an employee to ask for alternative arrangements to enable family-friendly policies. Just because he's got it, doesn't entitle you to have it - unless your personal circumstances are similar, which they don't seem to be.
Your 2 hour or 3 hour lunch-break scenario would be a change in your T&Cs, so, no, the employer can't just demand that, the same way I advised you that you can't demand a 30 minute break. Such proposed changes would have to be subject to consultation. Perhaps I can recommend taking up reading books in your break for relaxation purposes in the remaining time.
I've had enough trouble in my HR professional life with employees whining to me wanting 'me too' policies applied, demanding 'its not fair'. In general I find a high correlation between such employees and a lower value to the organisation, as assessed by that organisation. However I'm sure that couldn't possibly be true here.