"i could have those hours as well taking my working hours to 36 per week, i asked her if my contract would be changing she said no but as far as everyone was concerned those hours were mine permanently and would not be taken off me and if anyone asked my contract had changed"
This is hog-wash and she is conning you.
The way a contract is changed is one of two ways:
1) the employer writes to you - dear sb382, confirming my conversation with you, your weekly hours are now 36 hours per week as from xyz. Your rate of holidays accrual will now be calculated from the new figure. All other terms of your contract are unchanged. Ms Boss"
2) It becomes what is called an implied term of your contract because it has been this way for a 'long' time. There is no definition of 'long' but let's say at least 3 months.
You can try forcing the issue like this:
Write to the employer along the following lines "Dear Boss, further to our conversation earlier, you advised me that my hours would now be at least 36 hours per week. For the sake of clarity in the future I am writing to you to confirm this conversation".
That should give her something to think about - if she does nothing you're home and dry, to refute it she is going to have to write back to you.