It was an option within the hosting overview tab on my wp dashboard then under ‘tools’ to turn on captcha for log ins. We just turned that off and it was resolved. Not sure if it to do with the host. We use Tsohost.
Thank you so much for your reply. I found the issue this afternoon within the hosting dashboard. Captcha had been turned on for all logins (not sure when or by who!) but turning it off fixed things 🙂
