Automated Candidate job applications

Summary:

In the past 3 weeks we've had 47 candidates apply for various positions which have definitely been created automatically by a bot. They have different names and email addresses but have the same home address and telephone number. 15 applied within 3 seconds! 

Content (required):

We're a housing association based in the UK and the candidate address is from Los Angeles. Each job submission has a text file and our cyber team have verified that the file contains nothing malicious. 

Has anyone experienced this and if they have, how to stop it? The Career Section - User accounts setting 'User account validation on creation' doesn't work and MOS have also confirmed the setting is 'non-functional'.