Injury claim help please

I was hit by a van back in March when I was stationary at traffic lights. My car was written off and I have back and neck injury and was off work for 6 months.

My question is in regards to my loss of earnings.
I’m contracted to work 24 hours a week but work 13 hours overtime a week but I only take 8 hours paid and save the other hours to use as extra holiday in the school holidays.

The insurance company say that this is not classed as loss of earning, even though I will now have to take unpaid leave or pay for childcare in the holidays.

Also I have used the holiday i have to reduce my working week as I’m still not right but they will not included this in my claim ??

Any advise on what can be classed as listed earning would by really appreciated

Thank you