OK aGal.
If your school is oversubscribed re. the catchment are, it means they now have to apply their oversubscription criteria, which you will be able to find on the school or the LEA website (hopefully).
As a rule of thumb, these are: 1. Children in care 2. Children with social/medical reason for applying to this school 3. Children with sibling at this school 4. Places allocated to other children on a distance basis.
That is a rule of thumb only; faith schools are v. different and LEAs and schools often have little variations in their priority order.
So, if you have dc at this school already and they will be there when your little one applies, you need to make this very clear on the form.
If you have looked at the order of priority and you think that you are not close enough to get in under distance allocation (you're near but not that near) and your dc will have no current sibling at the school (or the sibling priority is not in place at this school), then you are essentially applying for a place on social/medical needs grounds.
As a rule of thumb, there are about 2 per 30 places allocated on these grounds (Please anyone - feel free to correct all this). I don't know where you are but where I live, these places are considered, with good reason, with great care.
The places are allocated on the social/medical grounds of the child. So you have to prove why your child needs that place. So although you can say that it's going to lose you work, you need to show that this will have an adverse effect on your child. And you need to show supporting evidence of everything you assert.
Now, I could be wrong about all the above. The situation may not be quite the same where you are. It may be enough to say that you will lose work and it will be inconvenient for the parents of your mindees. BUT that would not be enough in most areas.
Is it too late to go and have a chat to the admissions secretary?