Unable to update IPadOS 13.6.1

Ipad Air will not "download and install" this update.

Each time I click on Download / Install it reverts to the words "Update requested" and remains there ... for hours.

I have more than 50% of my storage available.

It has not already downloaded - I have checked general / storage / apps and its not there

Please note:

I am downloading through iphone hotspot.

Speed is fine: Using Ookla Speedtest (on ipad), download speed is 13MB

Please suggest solutions. Thanks