Thank you for taking the time to reply [smile}
sorry to quote your post but I can't see another way of answering your question.
Can I double check the facts? You have to do 20 hours a week and you offer up available times and they then accept the ones that match their needs? no I Offer the days I can work they fit me in accordingly
And some hours you get paid standard rate, some hours you get paid premium rate? I get paid Standard rate for my 20 hours anything over 30 I get time and a half any Bank Holidays and sundays (I have opted out of sunday working )I would get double pay.
And on certain weeks you are offering to do only hours which (mostly) fall in the premium rate category rather than the standard rate category? No out of 8 BH this year my DP's shifts have allowed me to work the last 3. I have not wanted to do them all
And because of that, they are saying they will take the standard hours that you offer to do, but not the premium hours you are offering up? which leaves you short of the 20 hours and means you are using up holiday? yes
If so, then I think that you don't really have a leg to stand on. I would say that it could be seen as unfair of you to only make yourself available during premium rate hours.
If it is the case that each week you offer yourself for rotas that total, say, 30 hours, including at least 20 standard hours and some premium hours, and that they were not filling your 20 hours from the standard pay rotas you had offered to be on, then you might have a justfiyable complaint, but as it is I think they are doing exactly as you would expect them to: they have paid upfront for the ability to call staff in without paying extra, and they are now 'banking' that benefit. I would be surprised if they had done anything different. Forcing you to work bank holidays or Sundays might in certain cases be unfair, but forcing you NOT to almost certainly isn't, unless you have a clear agreement that some of your work WILL fall on such dates.
I should add a health warning to the above in that this isn't one I have come across before in employment law, so I am just going by gut instinct on some of this. It is an odd one. I could be wrong. But TBH I think that in cases like this there should be flexibility on both sides - and where there are bank holidays etc then you should offer them up enough options for them to take your 20 hours out of standard pay times, rather than expect them to pay more to use you when they can use someone else for less.
It is unfair on you because you now lose all possible premium rates. But then your colleagues are now having to do 25% more unsociable hours than before, because of the people who refused the move (and who are now excluded from the weekend work), so they may be 'out of pocket' too. but that was their choice surely ?
I would be interested to see what flowery/ribena think about this one...