This is from the CICA Official Website:~
How long will this take?
We may take a year or more to make a final decision. More complex cases can take longer, especially if they involve loss of earnings or future medical expenses.
Wherever possible, we settle applications by offering a single payment of compensation - a final award. But we can only do this if your medical condition and financial losses are clear. If there is likely to be a long delay in getting this information, but you are clearly eligible for compensation, we may be able to pay some of the money before the final award is made. We call this an interim payment and we would deduct it from your final payment.
I am assuming that by "to come through" you mean how long for the CICA to make a decision? If so,the above applies.
Here is the Official Website,so you can see it in full:~
http://www.cica.gov.uk/