Example URL:
https://111.service.nhs.uk/PW755/Male/24/start?age=24&digitalTitle=Headache%20and%20migraine&entrySearchTerm=headache&filterServices=True

Steps to reproduce the problem:
1. Choose an answer, click Next
2. Choose another answer click next
3. Press the browser's back button
4. If you are in Chrome on iOS, you will now be on page 1 instead of page 2.

What is the expected behavior?
You should be on page 2, and would be on any other browser.

What went wrong?
I think the state isn't being saved in history due to being a POST. It is not using the web history api or anything like that.

Does it occur on multiple sites: N/A

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 61.0.3163.102  Channel: stable
OS Version: 11.0.2
Flash Version: