Soft AP, max page size we can send

I wanted to allow my customer to connect to my P1 via the AP to allow them to make changes to Its operation.
Originally I had a small page which just had a few radial buttons and some text fields. Worked just fine.
I now have expanded the site to add more options, and now its not serving the whole page.
I have discovered that my removing elements from the page one by one until its started working that it’s a issue with how much we can send. So I am curious what is the max length for a string we can send before it chokes, and can it be increased?

I.E.

const char index_html[] = "<!DOCTYPE html><html><head><meta name='viewport'...";

I believe the underlying WICED function for Soft-AP has a 65535 byte limit.