If they are not ok, move on to the next one and say "not a problem, see you next month"
agreed 100%
are zero hour contracts legal?
yes
‘Zero contracts’ are contracts of employment which do not specify any number of hours that the employee will be required to work. They are common for shop workers. The contract says that instead of working a specific number of hours per week, you must be ready to work whenever you are asked.
‘Key time’ contracts are those where you are guaranteed some work, but are not guaranteed regular hours each week.
The problem with zero and key time contracts is that you are only paid for the time you work, so even if you have to wait on work premises or be at home waiting by the phone, you may not be paid for this waiting time. However, legally, if you're on a zero hours contract, you are entitled to be paid for any time you have to be on work premises waiting for work to come up, unless your contract of employment says otherwise. You should be paid your normal hourly rate or, at the very least, the National Minimum wage
the above was tken off another site