Interesting... did you try to use the scrollbar?

yes i have used the scroll bar and there is no log in button at all on the screen..i can put all my details in to log on but as i said, there just is no button to finish the log in procedure..always was before but after one off the updates for firefox the problem appeared..now have to use microsoft edge which is ok but have always preferred to use firefox as my browser for everything...i've not changed any settings in firefox or on my computer nor do anything different and everything is fine for every other site...it is only the mygov site that i get the problem on..like i said,i now use microsoft edge for that site so no big problem but would prefer to not to use edge..

You can try to zoom out the page.

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, DuckDuckGo PE, Disconnect, Ghostery, Privacy Badger, uBlock Origin), always make sure such extensions do not block content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

You can check for issues with Enhanced Tracking Protection and Total Cookie Protection.

• https://support.mozilla.org/en-US/kb/total-cookie-protection-and-website-breakage-faq
• https://support.mozilla.org/en-US/kb/introducing-total-cookie-protection-standard-mode